Rochester, MissouriRochester is an unincorporated community in Andrew County, in the U.S. state of Missouri. The community is part of the St. Joseph, MO-KS Metropolitan Statistical Area.HistoryRochester was platted in 1848. The name is a transfer from Rochester, England. A post office called Rochester was established in 1844, and remained in operation until 1935.GeographyRochester was located just east of the Platte River.