----------------------------Original message---------------------------- SOUTHERN BOUNDARY OF THE UNITED STATES MILES Texas (along the Rio Grande, approximate)_____________ 1241 New Mexico____________________________________________ 179.5 Arizona (19.1 miles along the Colorado River)_________ 372.5 California____________________________________________ 140.4 ______ TOTAL 1933.4 Miles Source: Boundaries of the United States and the Several States Geological Survey professional paper 909: 1976 Page #23.