Yuma’s area of responsibility is located in the southwest corner of Arizona and is comprised of approximately 181,670 square miles of primarily desert terrain divided between California and Arizona. We secure 126 miles of United States Border from the Imperial Sand Dunes in California to the Yuma-Pima County line. This area consists of vast open deserts, rocky mountain ranges, large drifting sand dunes and the ever changing Colorado River.
https://www.cbp.gov/border-security/along-us-borders/border-patrol-sectors/yuma-sector-arizona