Resident Population in Kay County, OK was 43.43700 Thous. of Persons in January of 2024, according to the United States Federal Reserve. Historically, Resident Population in Kay County, OK reached a record high of 53.11300 in January of 1983 and a record low of 43.43700 in January of 2024. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Kay County, OK - last updated from the United States Federal Reserve on April of 2026.