• Explore and Discover One of the Last Frontiers in the World ...

    Jewel Cave

    National Monument South Dakota

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  • Caution - Roadwork on Highway 16 - Expect Delays

    Construction projects both along highway 16 and the Jewel Cave parking lot are planned during this summer season. The visitor center will be open daily, 8:00 a.m. – 5:30 p.m. Tours are scheduled throughout the day. No reservations for cave tours. More »

Environmental Factors

It might seem that the cave is isolated from the surface world, and that our activities above the cave would have little or no effect on the cave below. However, that is not entirely true. Wherever moisture from rainfall or snow melt is able to seep underground, a connection is made between the surface and the cave.

Jewel Cave National Monument strives to maintain the natural quality and quantity of water entering the cave, but the infrastructure that has provided opportunities for park visitors (the parking lot, visitor center, restrooms, administrative facilities, etc.) has in some cases changed the natural hydrology.

Developed areas cause runoff, which redirects water. Some areas of the cave may now be wetter than they were naturally, and others may be drier. Such changes in hydrologic patterns can have an effect on how and where speleothems (cave formations) will grow.

Forested areas above Jewel Cave typically direct less water into the cave than open, grassy areas. This is because trees use more rainwater than grasses do. The Jasper Fire killed many pine trees, and as a result, more rain water is expected to enter the cave.

The fire opened up the meadows to native plants such as blanketflowers, purple coneflowers, and western wheatgrass. Unfortunately, the fire-disturbed land also encouraged the growth of exotic plants such as common mullein and Canada thistle.

Did You Know?

Large cave passage / Marc Ohms photo

The largest room discovered in Jewel Cave is called the Big Duh. It measures 570 feet long, is 180 feet wide at its widest point, and is 30 feet tall.