Uncertain is a city in Harrison County, Texas, United States. According to the 2010 census, the city population was 94, down from 150 at the 2…Uncertain is a city in Harrison County, Texas, United States. According to the 2010 census, the city population was 94, down from 150 at the 2000 census. In 2020, it had a population of 85. The city of Uncertain was incorporated in 1961 as a Type B general law city, with a mayor and five aldermen on an at-large basis.