Longview is a city in Gregg and Harrison counties in the U.S. state of Texas. As of the 2010 Census, the population was 80,455. Most of the city is located in Gregg County, of which it is the county seat; a small part extends into the western part of neighboring Harrison County. It is located in East Texas, where Interstate 20 and U.S. Highways 80 and 259 converge just north of the Sabine River.