Generally you can find them at the courthouse.

This link gives a bit of an overview, but keep in mind it is for Oktbbiha Co - poke around for other MS inspiration/hints on the site

http://sturgisms.homestead.com/educable.html

For some places they have been microfilmed or transcribed

http://sturgisms.homestead.com/research.html

check to see if Jefferson Co has a comparable site!!

www.raogk.com

sometimes has volunteers in the area who can help

This search screen from familysearch.org lets you search for what has been microfiled for your area

try a place search for Jefferson part of ississippi

lots of goodies you can order in to your local FHC or at many larger libraries