Question

what line of latitude was used to divide free and slave territories

Answer 1

The line of latitude historically used to divide free and slave territories in the United States was the Mason-Dixon Line, which is located at approximately 39°43′ N (39.716° N). However, in terms of geographical demarcation established by legislation, the Missouri Compromise of 1820 set the latitude line at 36°30′ N. This line was significant in determining the legal status of slavery in the territories of the Louisiana Purchase, where areas north of this latitude were designated as free territories, while those to the south were open to slavery.