Oak, MissouriOak is an extinct hamlet in west-central DeKalb County, in the U.S. state of Missouri.The community is on Missouri routes 31 and 6 8.5 miles west of Maysville and five miles north of Clarksdale.HistoryA post office called Oak was established in 1894, and remained in operation until 1906. The community most likely was named for oak trees at the town site.DemographicsOak was incorporated during the 1930 US census. Its population then was 16.