Which agreement established 36° 30’ N as the dividing line between new slave states and new free states in the West?

The Missouri Compromise of 1820 set 36° 30′ N as the boundary for slavery in much of the western territory gained through the Louisiana Purchase. North of that line, slavery was prohibited in new states (with Missouri as an exception); south of it, slavery could be permitted. The correct choice is the Missouri Compromise.

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