Columbian mammoth fossil; photo by Wayne Hsieh on Flickr (noncommercial use permitted with attribution / share alike).
South Carolina designated the Columbian mammoth as the official state fossil in 2014, prompted by a letter from 8-year-old Olivia McConnell of New Zion to her state legislator pointing out that the state had no official fossil. She suggested this particular animal because in 1725 slaves discovered a tooth from a Columbian mammoth on a South Carolina plantation.
The Columbian mammoth (M. columbi, also known as the Jefferson mammoth, M. jeffersoni) appeared in the late Pleistocene. Its range covered the present United States and as far south as Nicaragua and Honduras.