Iliff was born on December 18, 1831, in
McLuney, Ohio to Salome Reed and Thomas Iliff. He attended
Ohio Wesleyan in
Delaware, Ohio but did not graduate. In 1857, at the age of twenty-six, his father gave him $500 in cash, and he moved to Ohio City, Kansas, where he opened a
retail store. In 1859, gold was discovered in
Colorado. He moved to
Denver, Colorado to open a new
retail store on Blake Street, trading supplies for livestock from new immigrants, then fattening them on the open range and using the profits to buy land in northeast Colorado, creating the largest ranch in Colorado history, where he raised as many as 35,000 heads a year to sell to
Union Pacific construction crews, becoming a millionaire known as "the Cattle King of the Plains", leaving his fortune to found
Iliff School of Theology. == Death and legacy ==