Building a Border: The Material Transit of Scientific Labor.

This article focuses on the U.S.-Mexico Boundary Commission (1849–1855), a joint effort to survey and demarcate the new border established by the Treaty of Guadalupe Hidalgo (1848) and the Gadsden Purchase (1854). It examines how the commission's scientific corps, primarily trained at the U.S. Military Academy at West Point, employed embodied surveying practices and astronomical observation to produce both the physical border and scientific personhood, transforming Indigenous territories into a quantifiable national space. The article highlights the challenges posed by the environment and Indigenous presence, the technical and disciplinary training of surveyors, and the role of scientific fieldwork as a mobile technology of place-making integral to state sovereignty and settler colonial expansion. Despite difficulties in physically marking the border, the commission's precise measurements and reports established an enduring, mathematically defined boundary recognized by the state.