The United States shares 5,525 miles of land border with Canada and 1,989 miles with Mexico. Monitoring these borders, which is the responsibility of U.S. Customs and Border Protection (CBP), is an enormous task. Detecting, and responding to, illegal activity while facilitating lawful commerce and travel is made more difficult by the expansive, rugged, diverse, and thickly vegetated geography that spans both often-crossed borders. To help mitigate the challenges to border surveillance, a group of researchers at MIT Lincoln Laboratory is investigating whether an airborne ladar system capable of imaging objects under a canopy of foliage could aid in the maintenance of border security by remotely detecting illegal activities. Their work will be presented at the 16th Annual IEEE Symposium on Technologies for Homeland Security to be held April 25-26 in Waltham, Massachusetts.