Oregon Caves National Monument is a national monument in the northern Siskiyou Mountains of southwestern Oregon in the United States. The main part of the 488-acre (197 ha) park, including the marble cave and a visitor center, is located 20 miles (32 km) east of Cave Junction
, on Oregon Route 46.
A separate visitor center in Cave Junction occupies 4 acres (1.6 ha) of the total. Both parts of the monument, managed by the National Park Service, are in southwestern Josephine County
, near the Oregon–California border. The climate is generally mild even at the cave's elevation of about 4,000 feet (1,200 m) above sea level, but icicles can form at the cave entrance, and winter snow sometimes blocks the park highway.
Oregon Caves is a dissolution cave, with passages totaling about 15,000 feet (4,600 m), that formed in marble. The parent rock was originally limestone that metamorphosed to marble during the geologic processes that created the Klamath Mountains, including the Siskiyous. Although the limestone formed about 190 million years ago, the cave itself is no older than a few million years. Valued as a tourist cave, the cavern also has scientific value; sections of the cave that are not on tour routes contain fossils of national importance.
Oregon Caves National Monument is located in the Siskiyou Mountains, a coastal range that is part of the Klamath Mountains of northwestern California and southwestern Oregon. The main part of the park consists of 484 acres (196 ha) in the Rogue River
– Siskiyou National Forest, about 6 miles (9.7 km) north of the Oregon–California border in Josephine County, Oregon.
Oregon Caves National Monument is open year-round, although snow sometimes blocks the road to the park. Cave tours are offered from mid-spring (mid-April) to late fall (early November), and the visitor center is open when the cave is open for tours. The schedule varies from season to season, but tours generally start no earlier than 9 a.m. and no later than 6 p.m. except for candlelight tours offered on Fridays and Saturdays at 6:30 p.m. between late May and early September.