Slavery was prohibited in states north of the 36°36', and this line continued west until California, which was completely admitted to the Union as a free state. In turn, slavery was allowed beneath the line. Missouri, on the other hand, was allowed into the Union as a slave state. This allowed for the amount of slave and free states to stay balanced to preserve the status quo in Congress.
The compromise divided the lands of the Louisiana Purchase into two parts. Slavery would be allowed south of latitude 36 degrees 30'. But north of that line, slavery would be forbidden, except in the new state of Missouri.
