Answer - after the Missouri Compromise there were:
<h2>12 free states</h2><h2>12 slave states</h2>
The Missouri Compromise (1820) admitted Missouri into the Union as a slave state with Maine being added as a free state at the same time, to keep the balance of slave and free states equal. It also prohibited any future slave states north of the latitude line 36 1/2 degrees north of the equator in territories of the Louisiana Purchase, with the exception of Missouri (north of that line) being admitted as a slave state.
