Osage Hills Hiking Club will expand its year-round series of "Explore the Outdoors!" activities Saturday when the first-ever Earth Day Hike is held at Osage Hills State Park.

Three different hiking courses are to be offered for beginning, intermediate and experienced hikers. Registration of hikers begins around 12:30 p.m. at Shelter No. 1 of the park, which is located 13 miles west of Pawhuska off U.S. Highway 60. The hikes are scheduled to begin at 1 p.m.