Amphibians and Reptiles in Callahan County: Texas Cooperative Wildlife Collection list of species found in the county.
Butterflies of Callahan County, Texas: Information about and pictures of all the known species of butterflies in the county.
Callahan City - Texas Ghost Town: Short profile of the town.
Handbook of Texas Online : Callahan County: Current and historical information about Callahan County.
The Political Graveyard: Callahan County: Lists politicians who lived or died in the county.
YBLost: Callahan County: Callahan County, Texas public record information.
