Pampa is a city in Gray County, Texas, United States. Its population was 16,867 as of the 2020 census. Pampa is the county seat of Gray Cou…Pampa is a city in Gray County, Texas, United States. Its population was 16,867 as of the 2020 census. Pampa is the county seat of Gray County and is the principal city of the Pampa micropolitan statistical area, which includes both Gray and Roberts Counties. Pampa is named after the Pampas Lowlands in Argentina, Uruguay, and southern Brazil.