On December 5, 1848, President James K. Polk
transmitted his annual message to Congress. He used this map as an exhibit to illustrate his desired plan for the land acquired through the Treaty of Guadalupe Hidalgo that ended the Mexican-American War earlier in the year. The land included the present-day states of California, Nevada, and Utah, as well as parts of Arizona, Colorado, New Mexico, and Wyoming. The map shows the latitude of 36°30' established in the Missouri Compromise of 1820: Slavery was prohibited in the Louisiana Territory in areas north of this latitude, and Polk advocated extending the prohibition to the Pacific Ocean to cover the newly acquired acreage. The table on the left-hand side describes the territories and their boundaries and lists the square mileage of land that fell north and that fell south of 36°30'. The table on the right-hand side tallies the total square mileage of free states (454,340 square miles) and slave states in the Union (610,798 square miles). The Compromise of 1850, actually a series of different bills, resolved the status of the new territory and diffused sectional tension over slavery for a time.