Base map from U.S. Geological Survey State Map.; "Published in accordance with Act of Congress approved Nov. 9, 1921, creating the Federal Aid Highway System."; "Data corrected to Dec. 31, 1927."; "Approved Federal Aid Mileage Iowa ... 7,212.00." sheets 79 x 56 centimeters Scale approximately 1:500,000; 1 inch = 7.891 miles General Map Collection