Octagon City is a ghost town in Allen County, Kansas, United States. It was a failed intentional community that was founded in 1856 about six miles (10 km) south of Humboldt, Kansas near the Neosho River. It was created by the Vegetarian Kansas Emigration Company, headed by prominent vegetarian Henry Clubb and entrepreneurs Charles DeWolfe and John McLaurin. The original intent was to build a vegetarian commune on the south side of the Neosho River for vegetarians only, but investor interest in a non-vegetarian moral community was much higher and so the decision was made to build Octagon City on the north side of the Neosho River to make the entire project sustainable.