Patrolling the Border Law and Legal Definition

According to 8 CFR 287.1 [Title 8 Aliens and Nationality; Chapter I Department Of Homeland Security (Immigration and Naturalization); Subchapter B Immigration Regulations; Part 287 Field Officers; Powers and Duties], patrolling the border means to prevent the illegal entry of aliens into the United States by conducting such activities as are customary, or reasonable and necessary, to prevent the illegal entry of aliens into the United States.