Celina is a city in Collin and Denton counties, Texas, United States. As of the 2010 census, Celina had a population of 6,028, up from 1,861 at the 2000 census.According to the United States Census Bureau, the town has a total area of 14.2 square miles (36.7 km2), of which 14.0 square miles (36.3 km2) is land and 0.15 square miles (0.4 km2), or 1.10%, is water.Running north/south through the town is State Highway 289 (locally known as Preston Road). It starts near downtown Dallas and terminates near Sherman. Celina is located about equidistant between downtown Dallas and the Oklahoma border.Being mostly farm and ranch land, the terrain is largely open fields on flat-to-gently-rolling terrain. The ambient air temperature is typically 4 to 6 °F cooler than Dallas 30 miles (48 km) south.