White Tank Mountain Regional Park, Regional park in Maricopa County, US.

White Tank Mountain Regional Park covers 29,271 acres of desert and mountain landscape in west-central Maricopa County, the largest regional park in the county. Most of the White Tank Mountains range lies inside its boundaries. The photograph shows tall columnar cacti with ribbed green stems and spiny arms rising from low scrub, with a rocky brown hillside behind them and a bright blue sky with scattered white clouds.

The land contains archaeological sites with remains of Hohokam settlements that thrived between 500 and 1100 CE in these canyons. These early desert dwellers developed ways to harvest and use the natural water resources found throughout the mountains.

The park's name comes from the white granite tanks, natural basins where rainwater collects. Eleven archaeological sites lie within the boundaries, including seven Hohokam villages occupied between 500 and 1100 CE. Petroglyphs, most of Hohokam origin and some possibly nearly 10,000 years old, are scattered throughout; visitors may photograph them but must not touch them.

The park has nearly 26 miles (42 km) of hiking trails, from easy walks to moderately difficult routes; the Waterfall Trail is a 0.9-mile (1.4 km) walk to a narrow canyon with a seasonal waterfall. Bicycling and horseback riding are allowed on many trails, and a separate 10-mile (16 km) competitive track is built for racing. Most of the park is wilderness where motorized vehicles are limited to existing roads and hikers must stay on marked trails. Flash floods can strike the narrow canyons during late-summer thunderstorms.

The tanks that give the park its name were carved by flash floods over thousands of years, hollowing out the white granite into natural water basins. These water-collection features remained essential to life in the desert and remain visible along several canyons today.