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is an unincorporated community in Pima County, Arizona, United States. It is located 11 miles (18 km) north of the Mexican border and 35 miles (56 km) west of the port of entry at Nogales. The European-American history of the area dates back at least to 1695, although the community was not founded until 1878. Arivaca has has the ZIP code 85601. The 85601 ZIP Code Tabulation Area had a population of 909 at the 2000 census.
The early history of Arivaca is obscure. It was probably a Pima or Tohono O'odham village, abandoned after the Pima Indian Revolt of 1751. Spanish settlers developed small mines, and in 1833 a Mexican land grant of 8677 acres was approved, which became La Aribac ranch, a Pima word for "small springs". Charles Poston bought the ranch in 1856, and the reduction works for the Heintzelman (Cerro Colorado) Mine were then erected at Arivaca. The Court of Private Land Claims eventually disallowed the Arivaca Land Grant. US Post Office was established April 10, 1878, with Noah W. Bernardas as the first Postmaster; still in operation at ZIP code 85601.