GAINESVILLE, TEXAS. Gainesville, county seat of Cooke County, is in the county's approximate geographic center, on Interstate Highway 35 about sixty-seven miles north of Dallas. In the 1840s the first settlers arrived in the area, attracted by the promises of the newly created Peters colony, which offered 640 acres to each head of family and 320 to each single man, plus land for a church in each settlement. In 1850 Gainesville was established on a 40-acre tract donated by Mary E. Clark.