Resident Population in Walla Walla County, WA was 61.56800 Thous. of Persons in January of 2023, according to the United States Federal Reserve. Historically, Resident Population in Walla Walla County, WA reached a record high of 62.61900 in January of 2020 and a record low of 42.17600 in January of 1970. Trading Economics provides the current actual value, an historical data chart and related indicators for Resident Population in Walla Walla County, WA - last updated from the United States Federal Reserve on May of 2024.