Seguin is a city in and the county seat of Guadalupe County, Texas, United States; as of the 2020 census, its population was 29,433. Its economy is primarily supported by a regional hospital, as well as the Schertz-Seguin Local Government Corporation water-utility, that supplies the surrounding Greater San Antonio areas from nearby aquifers as far as Gonzales County. Several dams in the surrounding area are governed by the main offices of the Guadalupe-Blanco River Authority, headquartered in downtown Seguin.
Seguin, named in honor of Juan Seguín, a Tejano Texian freedom fighter and early supporter of the Republic of Texas, is one of the oldest towns in Texas, founded just 16 months after the Texas Revolution began. The frontier settlement was a cradle of the Texas Rangers and home to the celebrated Captain Jack Hays, perhaps the most famous Ranger of all. At this time, the Seguin area was a part of Gonzales County, the remaining portion known as present-day Belmont. The Rangers had found this was a good halfway stop between their patrol points. It had been maintained as a base camp by the Rangers since the early founding of the Dewitt Colony.