Mormon Island is one of the islands formed by the multi-channel Platte River. During the 1884-1885 winter, several Mormon families camped on the tip of this island - the last of the Mormon migration to Salt Lake City. They chose the site because of the open stream and abundance of timber to repair their covered wagons. Three graves, a Mormon mother and two small children, remained on the island when the wagons rolled westward the following spring. The local people of the time named this place “Mormon Island,” the name it still carries today.
Source – Hall County Historical Society