A nation’s borders define the whole of that nation, and in the same gesture recognize the edges it shares with the rest of the world. Much like a porch offers a space for engagement with the outside world, Mariposa creates the opportunity for trade, commerce, and tourism between the United States and Mexico, one of the few openings in the nearly 2,000-mile boundary these countries share. Still, through its placement and command it must also determine who and what to keep out.

Security, control, granting or denying access: these are all critical functions of a land port of entry — or a porch. At times, these are expressed through the physical restriction of movement, holding vehicles or pedestrians until they can be admitted. This action can create a tense environment for everyone involved, including the staff keeping the port safe and operational. To mitigate this tension, the design of Mariposa leverages the built forms of the working spaces to create shaded, landscaped communal spaces that offer a necessary respite in what can be a hostile desert environment.

From abstracted lines in the sand defined by the geographical survey points, to a fortified boundary of steel, the border defining the boundary between the United States and Mexico has morphed, shifted, and evolved throughout history. When construction completed in 2014, the General Services Administration called Mariposa the new standard for land port of entry design because it emphasized the shared humanity of all at the port, from the staff that oversee the daily operations to the citizens of both nations that move through its safe passage. Three sets of footprints, cast into the surfaces of the concrete walls that enclose the port’s interior, remind us of the many journeys taken across this border.

At the frontier of our nation, our ports are charged with dueling requests: to welcome those that seek to enter while also attempting, at times, to withhold others’ entry—much like a porch provides a visitor’s temporary refuge before they are granted access or turned away. Mariposa embraces this reality: through generous daylight and transparency where pedestrians move through the port, or through the central Oasis where port staff can relax in a courtyard garden, without sacrificing anyone’s safety.

Ports are inherently spaces of exchange, facilitating the constant flow of people and goods, information and ideas. These interactions enrich the nations on both sides of the port and connect us more deeply with our world. Yet, with those exchanges comes challenges, like the balance of safety with speed, security with generosity, or connection with control. The swinging pendulum of politics on either side of the border—or at times far beyond it—frequently shapes the experiences of the people passing through land ports of entry, and, by extension, ports then become an expression of our binational relations.

The often irregular lines we draw to confine our understanding of the world are cast upon the organic forms of the earth. Similarly, the acts of construction are also destructive, permanently transforming the natural state of the land to take on the unnatural conditions of building. These ideas manifest simultaneously at land ports of entry. At Mariposa, the materials of the architecture and landscape seek to mend these acts, through the patina on the weathered steel and gabion walls to the persistent connection to the desert landscape and the vistas beyond.

Architecture transforms the act of crossing a border into an experience of shared humanity — a civic-scale porch shaped by gardens, daylight, and the desert’s enduring spirit.

A fractured border landscape is healed into a cohesive civic porch — where streamlined movement, shaded walkways, and resilient design foster a renewed sense of connection.

At Pacific Highway, the porch becomes an act of preservation — honoring the vernacular spirit of the region through modern craft, sustainable renewal, and a deep respect for place.

At San Luis, architecture becomes a guiding porch — channeling the rhythms of the land, light, and people into a crossing that honors resilience, labor, and the desert’s enduring life.