The Gadsden Purchase, in Spanish Venta de La Mesilla, was signed by James Gadsden and Antonio López de Santa Anna in December 1853 and took effect on June 8, 1854. It brought Mexico US$10 million and gave the United States the land for a southern railroad route.
It settled the border dispute that had left the Mesilla Valley in a contested strip, and it put Mesilla in the United States.