Nelsonville is an unincorporated community in Austin County, Texas, United States. According to the Handbook of Texas, the community had a population of 110 in 2000. It is located within the Greater Houston metropolitan area.

Austin County is a rural, agricultural dominated county in the U.S. state of Texas. As of the 2020 census, the population was 30,167. Its seat is Bellville. The county and region was settled primarily by German emigrants in the 1800s.