 US 30 was originally conceived as a part of the Lincoln Highway , the first transcontinental highway in the United States . A route through Iowa was chosen because of the important link between Omaha , Nebraska , and Chicago , Illinois . As the U.S. Highway System came into being in the 1920s , and the Lincoln Highway became US 30 , federal money started to pay for paving Iowa 's dirt roads . By 1931 , it had been paved across the entire state . 
