The longest street in America is Colfax Avenue in Denver, Colorado. It is 26.1 miles long, and was dubbed the "the longest, wickedest street in America" by Hugh Hefner in reference to some of the rougher neighborhoods through which the street traverses.
Colfax Avenue is only 0.1 miles shy of the distance of a marathon. Since 2006, an annual marathon has been held on Colfax Avenue. Colfax Avenue actually passes through three cities on its route, including Denver, Aurora and Bennett. In addition to the rougher areas that earned Colfax Avenue its nickname, Colfax Avenue once played home to some of the most elite addresses in all of Denver.