CALAVERAS CREEK. Calaveras Creek rises just south of Martinez in eastern Bexar County (at 29°25' N, 98°21' W) and runs southeast for fifteen miles to its mouth on the San Antonio River, one mile southwest of Calaveras in eastern Wilson County (at 29°13' N, 98°16' W). The creek is dammed just north of Elmendorf to form Calaveras Lake. It traverses rolling terrain surfaced by clay loam that supports mesquite and grasses.