Twenty-Five Mile Creek State Park is a public recreation area on the western side of Lake Chelan, northwest of the city of Chelan in Chelan County, Washington. The state park was a private resort that came into state ownership in 1972. It was operated under lease to various concessionaires until the state took over staffing in 1988. The park offers camping, a marina, fishing, waterskiing, bird watching, and mountain biking.