 The Main Street Historic District was added to the U.S. National Register of Historic Places in 1982.Tampico, Illinois, in southeastern Whiteside County, was founded in 1858 but settlers did not arrive in earnest until 1871, partially due to the swampy nature of the terrain.After the Chicago, Burlington and Quincy Railroad constructed a line through Tampico in 1871 growth was rapid but faced a series of major setbacks.