States System ofHighways Adopted for Uniform Marking by the American Association of State Highway Officials (地图). 1:7,000,000. Cartography by U.S. Geological
73英里。 Delaware Highways – US 9(页面存档备份,存于互联网档案馆) NJDOT – US 9(页面存档备份,存于互联网档案馆) Straight Line Diagram for the New Jersey portion of US9 from the New Jersey
The Big Table. U.S. Highways: From US 1 to (US 830). [July 4, 2006]. (原始内容存档于2006年2月15日). [自述来源] 维基共享资源上的相关多媒体资源:31号美国国道 Endpoints of U.S. Highway 31(页面存档备份,存于互联网档案馆)