Amphibians and Reptiles in Duval County: Texas Cooperative Wildlife Collection list of species found in the county.
Butterflies of Duval County, Texas: Information about and pictures of all the known species of butterflies in the county.
Handbook of Texas Online : Duval County: Current and historical information about Duval County.
YB Lost - Duval County, Texas: Provides names and addresses of county public officials and departments.