South of Central City, History Nebraska markers at the northwest corner of 15th Road and M Road tell the stories of the Mormon Trail, which ran along the north bank of the Platte about a mile south, and of the Lone Tree, a cottonwood about 50 feet tall that guided emigrants from the 1830s until it died in 1863 and blew down in 1865. Merrick County residents put up a 10-foot granite monument shaped like a tree trunk on the site in 1911; it was rededicated on July 3, 2011. The Union Pacific named its 1866 townsite Lone Tree, renamed Central City in 1875.