Miami is a city in Roberts County, Texas, United States. It is part of the Pampa, Texas micropolitan statistical area. Its population was 539 at …Miami is a city in Roberts County, Texas, United States. It is part of the Pampa, Texas micropolitan statistical area. Its population was 539 at the 2020 census. It is the county seat of Roberts County, as well as the only municipality in the county. The Roberts County Museum, located in Miami, contains many interesting artifacts and history of the county. Residences are mainly single family homes, with the Mesa View Apartments as the only apartments in the area. Miami has become noted for its annual cow calling contest, which occurs the first weekend in June and has been going for over 75 years.