Texas County Assessor's Office
210 North Grand Avenue Suite 201
Houston, MO 65483
- Texas County is a county located in the southern portion of the U.S. state of Missouri. As of the 2010 census, the population was 26,008. Its county seat is Houston. The county was organized in 1843 as Ashley County, changing its name in 1845 to Texas, after the Republic of Texas.