The U.S. Border Patrol operates checkpoints on U.S. roads, mainly in the southwest border states where most illegal entries occur. As part of a three-tiered strategy to maximize detection and apprehension of illegal aliens, Border Patrol agents at checkpoints screen vehicles for illegal aliens and contraband. This report assesses:(1) checkpoint performance and factors affecting performance; (2) checkpoint performance measures; (3) community impacts considered in checkpoint placement and design; and (4) the impact of checkpoint operations on nearby communities. Research included a review of Border Patrol data and guidance, and visits to checkpoints and communities in five Border Patrol sectors across four southwest border states. Illus.