AP U.S. History Notes: Period 5

April 12, 2024
AP U.S. History Notes: Period 5

Continue your AP test prep by reviewing these AP U.S. History (APUSH) Period 5 notes. Get an overview of what happens during Period 5 of APUSH, including key exam topics and essential vocabulary. Looking for more APUSH exam resources? Check out Barron’s AP U.S. History Premium Test Prep Book and our free AP U.S. History Podcast.

AP U.S. History Notes: Period 5 Timeline

This graphic gives a brief timeline of key events that took place during AP U.S. History Period 5.

APUSH period 5 timeline with key events (part one).
APUSH period 5 timeline with key events (part two).

AP U.S. History Notes: Period 5 Overview

The fifth period covered on the AP U.S. history exam took place between the years 1844-1877 and is referred to as “Slavery, Civil War, and the Transformation of American Society.” As the United States expanded its borders, economy, and population, sectional tensions—most notably over slavery—led to a civil war. The war and its aftermath dramatically transformed American society, ending the institution of slavery and raising fundamental questions about the nature of American democracy.

The acquisition and settlement of new territories in the western half of the North American continent opened up a question that many politicians had sought to avoid—should these new territories allow slavery? Most northern politicians were not abolitionists; indeed, abolitionism was a minority position in the North in 1850. However, the issue of the expansion of slavery became increasingly divisive in the 1850s. Some northerners adopted the free-soil ideology—the idea that lands out West should be open to small-scale farming, without competition from large-scale plantation agriculture using slave labor. By the end of the decade, more northerners were grappling with the moral issues around slavery. Positions became decidedly more entrenched on the eve of the Civil War.

The importance of the Civil War to American history cannot be overstated. This bloody war settled one of the most vexing issues in American history—the existence of slavery in an otherwise democratic country—and opened up space for broad debates about the substance of democracy in post–Civil War America.

10 Things to Know About AP U.S. History Period 5

1. As the American economy grew between the War of 1812 and the Civil War, many Americans continued the push ever farther into the continent. This westward movement had profound implications for Canada and Mexico as well as for American Indian nations within the borders of the growing United States. Finally, the acquisition of additional territory inflamed sectional tensions, as the debate over the expansion of slavery intensified in the decade before the Civil War.

2. The Mexican-American War proved to be an important turning point in the period leading up to the Civil War. Debates over the status of slavery, American Indians, and Mexicans in these newly acquired lands became heated in the years following the war.

3. As the United States expanded to the West, the question of whether new territories should allow slavery or not led to heated political controversies. These controversies intensified as the United States acquired additional territory in the Mexican-American War. The Compromise of 1850 sought to address these controversies, but resulted in a widening of the sectional rift.

4. Sectional divisions between the North and the South intensified in the decade leading up to the Civil War. These divisions resulted from the ideological debates around slavery, along with regional economic and demographic changes. The status of slavery in new territories brought these debates to the surface.

5. Northern and southern politicians tried repeatedly to compromise on the issue of slavery in the new territories of the United States in the 1850s, but these attempts proved unsuccessful.

6. Whatever trust existed between political leaders of the North and of the South broke down by 1860. The rancorous election of 1860 resulted in the election of the Republican candidate Abraham Lincoln and the secession of the southern states.

7. There are several key factors in understanding the Union victory over the Confederacy. The states that stayed in the Union comprised a larger population and a larger industrial capacity than the secessionist states. Both sides had strengths and weaknesses, but as the war progressed, the strengths of the Union—notably its material and population advantages—became more significant in achieving victory.

8. The decision to shift the focus of the Civil War from maintaining national unity to also eradicating slavery played an important part in the Union victory in the Civil War.

9. The impact of the Civil War and Reconstruction on American society was profound. Broadly speaking, the war changed the relationship between the states and the federal government. Specifically, the war made it clear that the United States was indivisible; secession would not be allowed. Most important, the Civil War ended the practice of slavery in the United States. The Civil War and Reconstruction initiated debates over redefining citizenship, especially when it came to women and African Americans.

10. The gains for African Americans during the Reconstruction period were short lived. After white southerners attained “home rule,” they carried out a series of policies that effectively sidestepped the protections of the Fourteenth and Fifteenth Amendments. Violence, and the threat of violence, further eroded the civil rights of African Americans. In addition, economic arrangements evolved that kept African Americans in a state of debt and poverty.

AP U.S. History Notes: Key Topics in Period 5

Manifest Destiny

  • “Manifest Destiny:” Many Americans came to believe that it was the “manifest destiny” of the United States to expand westward and extend its power in the Western Hemisphere. Manifest destiny refers to the movement of individuals to the West, but it also alludes to the political extension of United States territory. The term captured the fervor of the westward expansion movement, implying that it was God’s plan that the United States take over and populate the land from coast to coast.
  • Oregon Trail: Migrants to the West traveled along one of several overland routes. The most famous was the Oregon Trail, a 2,000-mile route from Missouri to the Pacific Northwest.
  • “Forty-Niners:” A large percentage of the 300,000 people who migrated to California came in 1849, thus their nickname, “Forty-niners.” A few people did strike it rich. However, very soon, the easily accessible gold was panned from riverbeds. Getting access to gold beneath the surface required capital-intensive methods. The necessary machinery was beyond the reach of ordinary prospectors.
  • The Morrill Land Grant Act: The Morrill Land Grant Act (1862) promoted secondary public education primarily in the West. Under the act, the federal government transferred substantial tracts of its lands to the states. The states could build public colleges on these lands, or they could sell the land to fund the building of educational facilities.
  • The Pacific Railroad Act: The Pacific Railroad Act (1862) and supplementary acts passed in the 1860s extended government bonds and tracts of land to companies engaged in building transcontinental railroads.
  • The Homestead Act: The government encouraged development of the West by passing the Homestead Act (1862), which provided free land in the region to settlers who were willing to farm it. The Homestead Act reflected the “free-labor” ideal of the Republicans.

The Mexican-American War

  • Texas Annexation: The election of 1844 put the issue of Texas annexation on the national agenda. Democratic hopeful James K. Polk promised to push for Texas annexation as well as for a resolution to a border dispute with Great Britain over Oregon, offering something to both southern and northern voters.
  • Rio Grande: Tensions between the United States and Mexico were brought to the surface due to a dispute over the southern border of the new United States territory of Texas. Mexico said the border was at the Nueces River. The United States insisted it was at the Rio Grande (the present-day border between Texas and Mexico), 150 miles to the south. In 1846, skirmishes in the disputed area led to war between Mexico and the United States.
  • Treaty of Guadalupe Hidalgo: In 1848, the Mexican government signed the Treaty of Guadalupe Hidalgo, giving up its claims to the disputed territory in Texas and agreeing to sell the provinces of California and New Mexico, known as the Mexican Cession, to the United States for $15 million. This territory includes present-day California, Nevada, Utah, and parts of Arizona, New Mexico, Colorado, and Wyoming.
  • Reservations: As early as 1851, the federal government pursued a policy of restricting American Indians to established reservations—confined areas that were set aside by the government. A major goal of the reservation system was to keep American Indians off lands that white settlers wanted to settle. Often the lands set aside for reservations were incapable of sustaining crops, reducing the inhabitants to utter poverty. Many tribal groups resisted being put into reservations.

The Compromise of 1850

  • Wilmot Proviso: Northern politicians tried, unsuccessfully, to ban slavery in territories that might be gained in the war by putting forth the Wilmot Proviso (1846). These politicians were not, for the most part, abolitionists, but they believed in the “free labor” ideal. They wanted additional land for white settlers to set up homesteads without competition from the slave system. The proviso was passed by the House of Representatives, where politicians from the populous northern states dominated, but failed in the Senate.
  • Popular Sovereignty: Senator Lewis Cass, the Democratic candidate for president in 1848, proposed a compromise measure on the question of slavery in the newly acquired territories. He came up with the idea that the question of slavery should be left to the people of a particular territory. This idea became known as popular sovereignty.
  • California: By 1850, California had enough of an American population to form a state (a population threshold of 60,000 was established by the 1787 Northwest Ordinance). Californians wrote up a constitution to submit to Congress in which slavery would be illegal. Southern senators objected to the admission of an additional free state.
  • Compromise of 1850: The most important elements of the compromise were the admittance of California as a free state, which pleased northern politicians, and a more stringent Fugitive Slave Law, which pleased southern politicians. Other measures included allowing New Mexico and Utah to decide the question of slavery based on popular sovereignty, accepting a new boundary between Texas and Mexico, and banning the slave trade (but not slavery) in Washington, D.C.

Sectional Conflict: Regional Differences

  • Nativism: The first half of the nineteenth century witnessed a dramatic increase in immigration from Europe, as well as a strong xenophobic nativist movement. Nativism was both an emotional impulse as well as an organized movement. Many Americans thought that the new immigrants, who were mostly non-Protestant, lacked the self-control of “proper,” middle-class Protestant Americans.
  • Fugitive Slave Act: Many northerners grew alarmed at the enforcement of the 1850 Fugitive Slave Act. The strict provisions of the 1850 act allowed slave catchers to bring the brutality of the slave system to the streets of northern cities. Many whites and free African Americans in northern cities even formed vigilance committees to prevent the slave catchers from carrying out their orders.
  • Uncle Tom’s Cabin: Sectional tensions were further inflamed by the publication in 1852 of the novel Uncle Tom’s Cabin. The novel, written by Harriet Beecher Stowe of the antislavery Beecher family, depicted in graphic and emotional detail the brutality of slavery. For many northerners, slavery now had a human face. The novel outraged southern supporters of slavery, who attempted to ban it.

Failure to Compromise

  • Kansas-Nebraska Act: In 1854, Senator Stephen Douglas of Illinois introduced the Kansas-Nebraska Act to the Senate. Douglas, who owned significant tracts of land in Chicago, hoped that the first transcontinental railroad would have a more northern route, using Chicago as a hub. Any railroad construction would have to be carried out in organized territory. The act called for dividing the northern section of the Louisiana Purchase territory into two organized territories, Kansas and Nebraska.
  • Dred Scott v. Sandford: The case involved the fate of a slave named Dred Scott, owned by a doctor serving in the U.S. Army. Scott and his wife, along with their owner, lived for a time in Illinois and in the Wisconsin Territory, areas where slavery had been banned by the Northwest Ordinance. Years after returning to Missouri, Scott sued for his and his wife’s freedom on the grounds that they had lived for a time in free areas and that made them free. The Supreme Court did not find Dred Scott’s arguments persuasive. First, the Court ruled that Scott was still a slave and did not even have the right to initiate a lawsuit. Next, the Court ruled that Congress had overstepped its bounds in declaring the northern portion of the Louisiana Purchase territory off-limits to slavery. The decision, therefore, invalidated the Missouri Compromise of 1820. Finally, the Court declared that no African Americans, not even free men and women, were entitled to citizenship in the United States because, according to the decision, they were “beings of an inferior order.”
  • “Free Labor” Ideology: Central to the Republican Party was the “free labor” ideology. This ideology upheld civic virtue and the dignity of labor and put a great deal of emphasis on economic growth and social mobility. It vigorously defended a free labor system that allowed hard-working individuals to achieve independence and property. The economic superiority of free labor to slave labor became a major part of the Republican argument against slavery.

Election of 1860 and Secession

  • Secession: Lincoln’s electoral victory in 1860 alarmed southern defenders of slavery to the point that leading political figures in the South were ready to secede. Even before Lincoln was inaugurated, seven southern states did secede (South Carolina in late 1860, Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas in early 1861).
  • President Lincoln: Once inaugurated, President Lincoln made it clear that he would not permit southern secession, but he did not want to initiate a war with the breakaway states. The presence of U.S. troops at Fort Sumter, in the harbor of Charleston, South Carolina, proved to be the spark that ignited the war.
  • Confederate States of America: The leadership of the nearly formed Confederate States of America decided that it would not tolerate the presence of the U.S. flag over Fort Sumter. In April 1861 Confederate president Jefferson Davis ordered bombardment of the fort, which was forced to surrender. This encounter constituted the opening shots of the American Civil War.

Military Conflict in the Civil War

  • Industrialization: The Civil War spurred rapid industrialization of the North. During the Civil War, the Union government required an enormous amount of war materials, from guns and bullets to boots and uniforms. Manufacturers rose to the occasion by rapidly modernizing production. These changes in production sped up the process of industrialization that was in its beginning stages before the war. Industrialization stimulated a long period of economic growth, turning the United States into a world economic power.
  • “Greenbacks:” Congress issued three Legal Tender Acts in 1862 and 1863, allowing the government to issue paper currency, or “greenbacks.” Unlike currency backed by gold or silver, greenbacks were backed only by people’s faith in the government. The value of greenbacks fluctuated as the war progressed.
  • Enrollment Act: One of the most significant episodes of resistance to Union policies involved riots against the Enrollment Act (1863), establishing a military draft, in New York City in July 1863. Protests initially focused on government draft offices. Protesters were particularly angry about a stipulation of the draft law that allowed men to pay a $300 commutation fee which exempted them from serving as a soldier. This substantial sum was well beyond most working-class men.
  • Anaconda Plan: The Union had a three-part strategy. First, the navy would blockade southern ports. The intent of this strategy, labeled the Anaconda Plan, was to prevent supplies from reaching the South and southern products from being shipped abroad. The second part was to divide Confederate territory in half by taking control of the Mississippi River. Finally, a contingent of troops would march on the Confederate capital of Richmond, Virginia and achieve victory.

Government Policies During the Civil War

  • Emancipation Proclamation: The edict ordered the freeing of all slaves in rebel-held territory as of January 1, 1863. Significantly, the order did not free slaves in the loyal border states or in Union-held areas of Confederate states. Of course, orders from the United States government did not hold any weight for Confederate leaders, so the Emancipation Proclamation did not initially free any slaves. However, the order clearly changed the goals and tenor of the war, and made clear that this was as much a war for the liberation of the slaves as it was a war to preserve the Union.
  • “Juneteenth:” On June 19, 1865, in Galveston, Union General Gordon Granger and his troops announced that “in accordance with a proclamation from the Executive of the United States, all slaves are free.” The anniversary of that announcement has long held significance in the African American community as “Juneteenth.”
  • The Battle of Gettysburg: The Battle of Gettysburg (1863) was a major turning point in the Civil War. Several months after the battle, President Abraham Lincoln went to Gettysburg to dedicate a military cemetery at the site. His address at the ceremony succinctly framed the Civil War in the larger context of fulfilling the democratic goals that were implicit in the founding documents of the United States.


  • Thirteenth Amendment: Slavery had been virtually destroyed as Union troops defeated the Confederacy. Yet, by the end of the Civil War, some slaves were still not freed, especially in areas that had not been under Confederate control, such as Kentucky and Delaware. The Thirteenth Amendment (1865) freed the remaining slaves but, more importantly, it enshrined in the United States Constitution that slavery was illegal in America.
  • “Ten Percent” Plan: President Lincoln was eager to quickly restore the Union. An initial goal of his was restoring southern representation in Congress. In 1863, he announced his “ten percent” plan. Under this plan, if ten percent of the 1860 vote count in a southern state took an oath of allegiance to the United States and promised to abide by emancipation, then that state could establish a new government and send representatives to Congress.
  • Black Codes: Immediately after the Civil War, in 1865 and 1866, Southern states passed Black Codes. These statutes regulated the activities of African Americans and in many ways recreated the conditions of slavery. Certain Black Codes forbade African Americans from owning land or owning a business. A central feature of these Black Codes was a broad and harsh set of vagrancy laws, which allowed for the arrest of freed people for minor infractions.
  • “Scalawags:” Southern whites who joined the Republicans were labeled “scalawags” by their Democratic opponents. Many southern white Republicans were former Whigs and sought to promote economic progress for the South.
  • “Carpetbaggers:” Many northerners came to the South to participate in Reconstruction. Some of these northern Republicans sought personal advancement in coming South; many were motivated by a desire to assist the former slaves in their adjustment to life as freed men and women. Southern Democrats labeled these northerners “carpetbaggers,” implying that they hurriedly threw some belongings in a carrying bag and traveled to the South to make a quick fortune.

Failure of Reconstruction

  • “Sharecropping” System: African Americans began to rent land. They would customarily pay “rent” with a portion of their yearly crop—usually half. This “sharecropping” system was somewhat of a compromise—African Americans did not have to work under the direct supervision of an overseer, and white plantation owners acquired cotton to be sold on the open market. After paying back loans for seed money and tools, sharecroppers were left with very little for basic necessities. The system created a cycle of debt, which prevented African Americans from acquiring wealth and owning land.
  • Jim Crow Laws: A series of segregation laws, known as “Jim Crow laws,” were passed in the southern states in the years following Reconstruction. These laws segregated public facilities, such as railroad cars, bathrooms, and schools. Furthermore, they relegated African Americans to second-class status in the South. These state and local laws first appeared in the South starting in 1881.
  • Fourteenth Amendment: The passage of Jim Crow laws in the South after Reconstruction was aided in part by a narrow interpretation of the Fourteenth Amendment by the Supreme Court. Advocates of civil rights for African Africans hoped that the Fourteenth Amendment (ratified in 1868) would prevent the implementation of Jim Crow laws.