Colossal Cave Mountain Park
Cave · Tucson & the Sky Islands
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Colossal Cave Mountain Park is built around one of the largest dry caves in North America, a 2,400-acre park southeast of Tucson also home to the 128-year-old La Posta Quemada Ranch. The draw is the cave's past as an 1800s outlaw hideout, where stagecoach bandits reportedly hid from the law; guided tours still lead through its stalactites and flowstone at a constant 70 degrees. Classic Tours run daily on the hour, 10am-3pm, with cave open 8am-4pm; adult admission is $24.
The formations here stopped growing when the underground water that built them found a new route decades ago; it now feeds the neighboring Arkenstone Cave, discovered only in recent years. The legend that put Colossal Cave on the map holds that local outlaws hid inside after robbing the Southern Pacific Express's Train Number 20 twice, once for $3,000 in cash and once for a haul of gold and silver Mexican dollars. Rancher Solomon Lick formally explored and named the cave in 1879, after an early visitor told him it was simply colossal, and ran the surface property as a stagecoach-stop resort with six rooms and a dairy. In 2025, cavers found a chamber still holding standing water, a surprise in a system long assumed to be completely dry.
What you see
Inside, dense clusters of finger-thin and bulbous kidney-shaped stalactites and stalagmites crowd the passages, with side chambers dropping into holes so deep a tossed rock takes a moment to hit bottom.
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