The island, La Grande Ile, was formed approximately 28 miles upstream and ended 12 miles downstream from the city. Named by French Fur traders in the late 1700s, it first appears on American maps in 1822 and 1823. When the north channel of the Platte River was dammed up to prevent flooding, the island disappeared. This marker was erected by theHall County Historical Society. On a second monument, a map shows the island's original location. It was erected in 1967 by the families of W.A. Hagge and O.A. Abbott.