This is a list of all counties and municipalities (municipios in Spanish) that are directly on the Mexico–United States border. A total of 37 municipalities and 23 counties, spread across 6 Mexican and 4 American states, are located on the border. All entities are listed geographically from west to east.
Mexico
Baja California Tijuana Municipality Tecate Municipality Mexicali Municipality
Sonora San Luis Río Colorado Municipality Puerto Peñasco Municipality Plutarco Elías Calles Municipality Caborca Municipality Altar Municipality Sáric Municipality Nogales Municipality Santa Cruz Municipality Cananea Municipality Naco Municipality Agua Prieta Municipality
Chihuahua Janos Municipality Ascensión Municipality Juárez Municipality Guadalupe Municipality (first occurrence) Práxedis G. Guerrero Municipality Guadalupe Municipality (second occurrence, since it borders Práxedis G. Guerrero on three sides) Ojinaga Municipality Manuel Benavides Municipality
Coahuila Ocampo Municipality Acuña Municipality Jiménez Municipality Piedras Negras Municipality Guerrero Municipality Hidalgo Municipality
Nuevo León Anohuac Municipality
Tamaulipas Nuevo Laredo Municipality Guerrero Municipality Mier Municipality Miguel Alemán Municipality Camargo Municipality Gustavo Díaz Ordaz Municipality Reynosa Municipality Río Bravo Municipality Matamoros Municipality
United States
California San Diego County Imperial County
Arizona Yuma County Pima County Santa Cruz County Cochise County
New Mexico Hidalgo County Luna County Doña Ana County
Texas El Paso County Hudspeth County Jeff Davis County (border at only one point, i.e., border length is zero) Presidio County Brewster County Terrell County Val Verde County Kinney County Maverick County Webb County Zapata County Starr County Hidalgo County Cameron County
See also International border states of the United States#Border with Mexico