Bavaria is divided into seven districts:
Oberpfalz, Niederbayern, Oberbayern, Unterfranken, Mittelfranken, Oberfranken, and Schwaben. Bavaria was ruled by the Wittelsbach family from 1180-1918. The best known is Ludwig II (1864-1886) who built the castles of Neuschwanstein, Linderhof, and Herrenchiemsee.

Border Changes
The southern portion of today's German State of Rheinland-Pfalz was once owned by Bavaria and was referred to as the "Rheinpfalz," "Rhennish Pfalz," "Rheinbayern," or "Palatinate," but it is no longer a part of modern Bavaria.
E-Mail Lists
Websites for Bavaria How to find ancestor records in Bavaria:
Beginner research and FAQ’s (frequently asked questions):
Maps – Internet
Historical maps of Bavaria from 1962 to the present:
LDS records
Bavarian Research Groups (see their links also) Southern Bavaria. Northern Bavaria.
State Archives (Main Archive) (Coburg Staatsarchiv)  (NiederBayern Staatsarchiv)  (Oberbayern Staatsarchiv)  (Oberfranken Staasarchiv)
Evangelical archives in Germany: Protestant records (Lutherischen Kirche in Bayern)
Catholic archives in Germany:
The GGS collection of Germanic Genealogy Books at Concordia University in St. Paul, MN has 7 books specifically on Bavarian genealogy. All of those 7 books are in English. Check the Library webpage for further information.