Resident Population in Grant County, OK was 4.08300 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Grant County, OK reached a record high of 7.11700 in January of 1970 and a record low of 4.08300 in January of 2023. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Grant County, OK - last updated from the United States Federal Reserve on May of 2024.