This building, winner of an AIA/NYS and two GSA Design Awards, was designed under the General Services Administration Design Excellence program for United States Border Patrol.It is located halfway between Los Angeles and San Diego, nestled among the rolling hills of the Temecula Valley just east of the Santa Ana foothills. The region is dry and sun-drenched, cooled each afternoon by a prevailing west wind from the Pacific Ocean. This architecture speaks to the landscape, the vital culture of borders, and the integration of sustainable design techniques. It responds to the arid climate of the region, creating a comfortable and sustainable environment for its users through orientation and passive ventilation. The building reflects a careful balance of security and accessibility as it recedes into the earth, presenting a landscape form that conceals the activities of the Border Patrol. The façade then breaks open to form a transparent entrance and an inviting public face.The buildings linear plan is oriented north/south to minimize solar gain and present a broad face to the prevailing westerly breezes. The combination of careful orientation, thermal mass, and air pathways allows much of the building to be passively cooled and ventilated.Additional sustainability features include the optimization of natural light through clerestory and sky lights and the management of water runoff through sub-surface retention gardens that foster indigenous plant groups. All materials are locally produced with high recycled/low embodied energy content. The agents’ entrance at the east elevation is constructed of Cor-Ten steel in the same pattern and proportion as the US/Mexico border fence. The agents, in their day-to-day use of the building, in effect walk through this fence and experience it as a threshold, a reminder of the permeability of borders.