County Origins
Denton County was created in 1846 and named for a preacher killed in a raid
The Texas legislature carved Denton County out of Fannin County in 1846 and named it for John Bunyan Denton, a preacher-lawyer who died in an 1841 raid.
John Bunyan Denton was a Methodist preacher and lawyer from eastern Fannin County. He was killed on May 22, 1841, during a raid against Natives in what is now northern Tarrant County. The county and its county seat both bear his name.
The legislature formed Denton County in 1846 from the large Fannin County territory. Early settlers moved in under an 1841 land grant. The county's first county seat was not Denton — it was a community called Pinckneyville, which was replaced by Alton less than two years later, and Alton was eventually replaced by Denton. Denton city was founded in 1857 specifically to serve as a central county seat.
Source to confirm: TSHA Handbook — Denton County