Fannin County is a county in the far northeast of the U.S. state of Texas, on the border with Oklahoma. As of the 2020 census, its population was 35,662. The county seat is Bonham.

Bonham is a city and is the county seat of Fannin County, Texas, United States. The population was 10,408 at the 2020 census. James Bonham sought the aid of James Fannin at the Battle of the Alamo. Bonham is part of the Texoma region in northern Texas and southern Oklahoma.