Camp Grayling is the largest National Guard training facility in the United States. In 1913, lumber magnate Rasmus Hanson donated over 13,000 acres of cut-over land to the State of Michigan for military training. Originally named the Hanson Military Reservation, the property is today called the Camp Grayling Joint Maneuver Training Center. It now covers over 147,000 acres in Crawford, Kalkaska and Otsego counties, and more than 10,000 military personnel from National Guard units in the Midwest, the U.S. Army, and the U.S. Army Reserve often train there each year. The eastern shore of Lake Margrethe lies within the camp's boundaries; it was known as Portage Lake until 1917, when the State Military Board renamed it to honor Rasmus Hanson's wife. Hanson Hills, on lands managed by Camp Grayling under a recreational lease from the National Guard, opened in 1929 as Michigan's first downhill ski area, drawing visitors on snow trains to Grayling and then by flatbed truck to the winter sports park, which added a 66-foot ski jump in 1934. In 1923, Clarence Johnson shoveled out the first ice slide at Collens Landing at Lake Margrethe, and in 1925 two slides were built at Division Hill, where water was carried from the lake in pails to maintain runs of 1,100 feet. Two soldiers from Michigan's 125th Infantry Regiment died while at Camp Grayling: Pfc. John A. Conroy of Company D succumbed to pneumonia in 1927, and Pvt. George A. Laine of Company A drowned in Frog Lake in 1939; both are buried in a small fenced cemetery atop Mount Franklin. In 2005, U.S. Marine Corps Reserve Lance Corporals Kevin Michalak of S Company and James Stine of H Company repaired a High-Mobility Multipurpose Wheeled Vehicle in a Camp Grayling maintenance bay while serving in the First Battalion 24th Marines, and in 2018 part of the 1194th Engineer Company took cover from the rotor wash of a National Guard CH-47 Chinook helicopter during casualty evacuation training there.