Buenos Aires National Wildlife Refuge, Nature reserve in Pima County, United States.

Buenos Aires National Wildlife Refuge is a nature reserve in southern Arizona featuring semi-desert grasslands interspersed with cottonwood and willow trees along waterways. The landscape combines open fields, riverbank vegetation, and rugged terrain that create habitats for hundreds of animal species.

The refuge was established in 1985 to protect a section of native grassland that once covered the Altar Valley. Its creation marked an effort to preserve this landscape before development and agricultural changes could destroy the natural conditions of the area.

The name comes from the Buenos Aires Ranch, whose land became the refuge in 1985. Visitors can walk the Arivaca Cienega and Arivaca Creek trails, both designated National Recreation Trails, and join guided access programmes run by the Friends of Buenos Aires NWR.

Multiple hiking trails are available for visitors, with varying difficulty and length depending on your preference and fitness level. Some border areas may be restricted, so checking conditions before you go helps you plan your time more effectively.

Researchers followed an old male jaguar here from 2004 to 2007; he had already been photographed in the area in 1996 and was known as Macho B. His range covered the mountains east and west of the Altar Valley, and at least one other jaguar was recorded during the same study. Macho B was later euthanized after being caught in a snare trap.