Gainesville is located north of Denton between Wichita Falls and Sherman along US 82 and I-35 on the banks of the Elm Fork of the Trinity River near Lake Kiowa and Moss Lake.
The seat of Cooke County, it is situated just south of the Texas/Oklahoma state line.
Gainesville's population grew steadily in the second half of the 20th century, surpassing 10,000 in the mid-1950s and 14,000 by the late 1980s, when the community reported more than 300 rated businesses. Businesses at Gainesville included an aircraft firm and a fishing-lure company, and the community also served as a shipping point for sand and gravel.
In the early 1990s Gainesville had 600 businesses and a population of 14,587.