Why did the south readily agree to making slavery illegal in the unorganized louisiana territory?

The South agreed to have the Louisianna territory become free states because they wanted the North to allow the passing of the Fugitive Act. The law basically allowed the Southern states to request the return of slaves that escaped the state. 

The native americans, spanish, french and americans all name places in our state. the word “arkansas” came from the quapaw indians, by way of early french explorers. at the time of the early french exploration, a tribe of indians, the quapaws, lived west of the mississippi and north of the arkansas river.