Fort Fillmore was a fortification established by Col Edwin Vose Sumner in September 1851 near Mesilla in what is now New Mexico, primarily to protect settlers and traders traveling to California. Travelers in the Westward Migration were under constant threat from Indian attack, and a network of forts was created by the US Government to protect and encourage westward expansion. Fort Fillmore was intended to protect a corridor plagued by Apache attacks where several migration routes converged between El Paso and Tucson to take advantage of Apache Pass.