Gregg County is a county located in the U.S. state of Texas. As of the 2010 census, its population was 121,730. Its county seat is Longview. It is named for John Gregg, a Confederate general killed in action during the American Civil War.
Gregg County was created in 1873. When the Texas State Legislature convened in January 1873, Democratic representative B. W. Brown of Upshur County introduced a bill to create a new county from parts of Harrison, Rusk, and Upshur counties. Under Brown's proposal, the county was to be named Roanoke and Longview was to be the county seat. The proposed name was later changed to honor Texas leader and Confederate Genearal John Gregg, and the county seat was determined by popular election. Harrison and Rusk counties resisted efforts to incorporate their portions. When Gregg County was created, it first consisted of approximately taken from Upshur County, and the Sabine River was its southern boundary. In April 1874 about south of the Sabine River in Rusk County was added to Gregg County. The third portion of about from Harrison County was never realized.
Texas Attorney General John Ben Shepperd, who served from 1953-1957, maintained a ranch in Gregg County near his native Gladewater. He also served on the Gregg County Commissioners Court for a brief period in 1949.