I said below that slavery did not expand after 1845. I correct my statement. The Missouri compromise expanded slavery in areas already claimed as free in 1820. Two areas the about the size of Rhode Island; one in northwest Missouri and another around what looks like present day Denver, Colorado, according to the map.

The territory now known as Nevada, Utah, Arizona and New Mexico were given the confusing legal status of "slavery is neither expressly legal or illegal".

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David Upton