The only data that I could find was a report that said that there had been 151 breading pairs of bald eagles in California in 2000. The US Fish and Wildlife Service have good web sites about endangered species, maybe you can find more there.Some information can be found here:
http://www.fws.gov/midwest/eagle/population/nos_state_tbl.htm

You also may find this website helpful:
http://www.fws.gov/endangered/recovery/milestone_b.html

A map of estimated breeding pairs can be found here:

http://www.fws.gov/migratorybirds/issues/BaldEagle/Breeding%20Pair%20MAP.FLT.pdf