From 1838 to 1879, early maps showed Hole-In-The-Mountain, or Mountain Pass, where Coteau Perce Creek drained southwest from Lake Benton to the Big Sioux. Explorers Nicollet and Fremont visited the Hole on July 6, 1838, then passed westward three miles north of here, visited Lakes Oakwood and Poinsett, and returned to Minnesota forty-three miles farther north. In 1857, Wm. H. Nobles, superintendent, and Samuel A. Medary, engineer, used the Hole for the Fort Ridgely and South Pass Wagon Road, the first made road into South Dakota, marked by rock fords and mounds to show the way. The road terminated at the Missouri, was 254 miles long, and crossed the Big Sioux at Medary. In 1857, Medary called the Hole the only known route favorable for a railroad through or over the Coteau des Prairies. The Dakota Central Railroad, later the North Western, confirmed that prediction in 1879, and Elkton, first called Ivanhoe, Aurora, and Brookings may owe their existence to the Hole, while Fountain and Medary, Brookings County's first county seat, became ghost towns after being left off the railroad.