Resident Population in Ottawa County, KS was 5.81800 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Ottawa County, KS reached a record high of 6.30000 in January of 1972 and a record low of 5.57200 in January of 1992. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Ottawa County, KS - last updated from the United States Federal Reserve on May of 2024.