Trading Post is an unincorporated community in Linn County, Kansas, United States, which is said to be one of the oldest continuously occupied locations in the state. In 1842 a United States Army fort was built there, but it was soon abandoned. The fort remained until probably at least 1900. It was used by troops travelling through the area during the American Civil War and a military post was established in 1861 and lasted until summer 1865.