Dayton is a city in Liberty County, Texas, United States. The population was 8,777 at the 2020 census. According to the United States Censu…Dayton is a city in Liberty County, Texas, United States. The population was 8,777 at the 2020 census. According to the United States Census Bureau, the city has a total area of 30.70 square miles, of which all but 0.04 square miles is land.