The Mariposa Land Port of Entry (MLPOE) is a 115,840 SF complex of buildings and inspection booths located on the U.S./Mexico border. Housing five government agencies, the project is one of the busiest land ports in the U.S. Sited on a small plateau surrounded by gentle ravines, MLPOE includes large areas of undisturbed desert habitat. Buildings are arranged to create an oasis-like north-south exterior spine with adjacent official car parking and landscaping. Roofs collect and channel storm water, which is stored underground and used for landscape irrigation. Integrally insulated Thermomass site-cast concrete walls, both durable and low-maintenance, are functional inside and out. Sustainable strategies integrated into the design and construction of the MLPOE project allowed it to earn LEED Gold level certification.