A map of the United States in 1821 showing the results of the Missouri Compromise of 1820 over the issue of prohibition of slavery. The map is coded to show the areas of the Free States, the Slave States, the Michigan Territory as Free...

A map of the United States showing the effects of the Compromise of 1850. The map is keyed to show the free states and slave states, and notes California admitted to the Union as a free state; the Nebraska Territory as free by the...

A map of the United States during the period of 1850 to 1850 showing the effects of slavery, the slave trade, and the abolition movement on territorial development. The map uses colored patterns to indicate the areas and phases of...

A map of the United States during the period of 1850 to 1850 showing the effects of slavery, the slave trade, and the abolition movement on territorial development. The map uses colored patterns to indicate the areas and phases of...

A map of the United States and territories at the time of the slavery prohibition issue in 1850, after the Missouri Compromise of 1820. The map is color-coded to show the areas where slavery was prohibited by State Law, slavery was...

A map of the United States and territories showing the free areas and areas open to slavery as established by the Missouri Compromise of 1820.

A map of the United States at the time of the passing of the Compromise of 1850 (September, 1850). This compromise was a series of bills attempting to resolve territorial and slavery issues raised by the Missouri Compromise (1820) and...

A map of the United States in 1821 showing the states and territories which either accepted or abolished slavery after the Missouri Compromise of 1820. The map is color-coded to show absolutely free states, states undergoing gradual...

A map of the United States in 1854 showing the results of the test-vote on the Kansas-Nebraska Bill in the House of Representatives, which would repeal the Missouri Compromise of 1820 and allow territorial settlers to determine if...