Humboldt is a city in Allen County, Kansas, United States. It is situated along the Neosho River. As of the 2020 census, the population of th…Humboldt is a city in Allen County, Kansas, United States. It is situated along the Neosho River. As of the 2020 census, the population of the city was 1,847. Humboldt, originally an American settlement named after Baron von Humboldt, was founded in 1857. Germans migrating from Hartford, Connecticut, began organizing a colony during the winter of 1856–57. They arrived in Lawrence, Kansas, in March 1857, and at the townsite on May 10, 1857. Orlin Thurston, a young attorney, moved to Humboldt during the summer of 1857 and put up a steam sawmill; he began sawing wood and building houses on the prairie side of town. The first frame building was erected by J.A. Coffey; and in May 1858, W.C. O'Brien opened the first gristmill in the county. The United Brethren Denomination erected the first church in 1859.