Mexia is a city in Limestone County, Texas, United States. The population was 6,893 at the 2020 census. The city's motto, based on the fact th…Mexia is a city in Limestone County, Texas, United States. The population was 6,893 at the 2020 census. The city's motto, based on the fact that outsiders tend to mispronounce the name as, is "A great place to live, no matter how you pronounce it."