Seguin br/Guadalupe County, Texas br/br/Text: Guadalupe County; formed from Gonzales and Bexar counties; created March 30, 1846. Organized July 13,1846; named for the Guadalupe River, to which this name was given by Alonso De Leon in 1689; Seguin, the county seat named in honor of Juan Nepomuceno Seguin 1806-1890.