Fort Payne is a city in and county seat of DeKalb County, in northeastern Alabama, United States. It is near Lookout Mountain. At the 2020 cen…Fort Payne is a city in and county seat of DeKalb County, in northeastern Alabama, United States. It is near Lookout Mountain. At the 2020 census, the population was 14,877. This city developed around a fort of the same name, built in the 1830s to intern the Cherokee tribe who were being rounded up by the military before being forcibly removed to Indian Territory in 1838 on what they called the Trail of Tears.