Union State Bank was founded on October 11, 1947 by a group of Texas ranchers in Carrizo Springs, Texas. In 1999, a branch opened in Kerrville, Texas. The Kerrville location became the bank's headquarters in 2004. The Carrizo Springs location was sold in 2005 so the bank's efforts could be concentrated on Kerrville and its surrounding communities.
Union State Bank is located at 600 Main Street in Kerrville, in the former Kerrville City Hall building. The building, originally constructed in 1937, was renovated by Union State Bank to preserve its historical significance and architectural art deco style. The unique post clock which sits at the corner of Main Street and Clay Street, is the bank's signature symbol.