Runaways and the Río Grande River: The Texas Underground Railroad to Mexico and Mexico's Resolve to Uphold the Río Grande River as a Line of Resistance to Slavery, 1836-1861

The tale of a runaway, an enslaved Black man or woman choosing to abscond, is nothing short of miraculous. Listen between the lines a runaway speaks, and their story will be found as a testament entailing multiple dynamics. Reflective of the unifying theme, this thesis investigates resistance to slavery in the Texas borderlands, from 1836 to 1861. This thesis examines the existing body of scholarship on Mexico-bound escape routes used by Blacks fleeing captivity. Moreover, in following the direction archival evidence points to, this thesis argues the existence of an Underground Railroad in Texas to Mexico that facilitated the escape of at least 4,000, perhaps up to 10,000 Blacks, to Mexico. The Texas Underground Railroad is an important segment of history that is little known about. Issues explaining the erasure of Mexico, inclusive of the paradigm in Texas public education further averting historical attention, are explained. Evidenced in this research is the formation of a multiethnic and interracial coalition of forces that arose in Texas to assist runaways to Mexico, which to effect, created a system of networking unique to Texas. These operatives or "architects" of the Texas Underground Railroad consist of ethnic Mexicans and Germans, primarily in central Texas, as well featuring contributive roles exhibited by Native Americans, plausibly Irish immigrants, white abolitionists, and free and enslaved Blacks. Following Mexico's loss of Texas in 1836, two spikes in the number of runaways occurred. The first one was in 1836 as part of the aftermath of the Texas Revolution, and another spike occurred following the formalization of the U.S.-Mexico border by the 1848 Treaty of Guadalupe Hidalgo. This thesis features the study component of geopolitics to reveal the long-standing tradition of enslaved Blacks equating protection behind Spanish, later Mexican lines. Relative to the various recourses drawn by Anglo enslavers, and much to Anglos' dismay, resistance to slavery became a source of national pride in Mexico. Concluding Mexico a safer haven than escape towards Canada, addressed are impacts felt in Mexican border communities such as Piedras Negras, Coahuila, Mexico, and factors responsible for the successful assimilation of runaways into Mexican society.