Kidder is a city in Caldwell County, Missouri, United States. The population was 323 at the 2010 census. The city was laid out in 1860 by H.B. Kidder of the Kidder Land Company in Boston, which was seeking to encourage non-slave owning European immigrants to settle along the Hannibal and St. Joseph Railroad which at the time was the furthest west railroad in the United States.