Herkimer is a census-designated place (CDP) in Marshall County, Kansas, United States.

[3] A post office was opened in Herkimer in 1878, and remained in operation until it was discontinued in 1974.

[4] The 2020 United States census counted 54 people, 26 households, and 22 families in Herkimer.

[10] The percent of those with a bachelor’s degree or higher was estimated to be 0.0% of the population, with a 11% margin of error.

[6] The 2016-2020 5-year American Community Survey estimates show that the median household income was $76,500 (with a margin of error of +/- $23,596).