Dublin is a city located in southwestern Erath County in Central Texas, United States. Its population was 3,359 at the 2020 census, down fro…Dublin is a city located in southwestern Erath County in Central Texas, United States. Its population was 3,359 at the 2020 census, down from 3,654 at the 2010 census. The town is the former home of the world's oldest Dr Pepper bottling plant. The plant was for many years the only U.S. source for Dr Pepper made with real cane sugar, instead of less expensive high-fructose corn syrup. Contractual requirements limited the plant's distribution range to a 40-mile radius of Dublin, an area encompassing Stephenville, Tolar, Comanche, and Hico.