The U.S. Census Bureau estimates , the five fastest-growing cities of any size between 2000 and 2008 were `` Saratoga Springs '' ( 1,501 % ) , `` Herriman '' ( 1,061 % ) , `` Eagle Mountain '' ( 934 % ) , `` Cedar Hills '' ( 209 % ) , and `` Lehi '' ( 146 % ) . According to U.S. Census Bureau estimates , the five fastest-growing cities of any size between 2000 and 2008 were Saratoga Springs ( 1,501 % ) , Herriman ( 1,061 % ) , Eagle Mountain ( 934 % ) , Cedar Hills ( 209 % ) , and Lehi ( 146 % ) .