Longest Caves Length Comparison (KM)
Compare the 10 longest caves, from Mammoth Cave at 685.6 km to Fisher Ridge at 209.2. Mapped exact passage lengths in km and miles with all NPS sources.
Visual comparison
All values
Click any row to load it as Entry A.
| Name | Value | Context | Source |
|---|---|---|---|
| Mammoth Cave Flint and Mammoth linked in 1972 at 232 km. | 685.6 kilometers | Kentucky, USA, longest known cave | NPS Mammoth Cave: 426 miles (686 km); showcaves 685,581 m |
| Sistema Ox Bel Ha Second longest system in the world. | 496.8 kilometers | Quintana Roo, Mexico, longest underwater cave | Showcaves statistics: 496,804 m (2024) |
| Shuanghe Water Cave Became third longest in 2023. | 417.7 kilometers | Guizhou, China, longest in Asia | Showcaves statistics: 417,696 m (2024) |
| Sistema Sac Actun Second longest underwater cave. | 376.7 kilometers | Quintana Roo, Mexico | Showcaves statistics: 376,700 m (2021) |
| Jewel Cave Fifth longest in the world. | 354.6 kilometers | South Dakota, USA | NPS Jewel Cave NM: 220.33 miles (354.59 km) July 2025 |
| Wind Cave Most complex 3D maze cave. | 268.8 kilometers | South Dakota, USA | Showcaves statistics: 268,808 m (2024) |
| Optymistychna Cave Longest gypsum cave in the world. | 264.6 kilometers | Ukraine, longest gypsum cave | Showcaves statistics: 264,576 m (2021) |
| Lechuguilla Cave Deepest in continental US at 484 m. | 242.1 kilometers | New Mexico, USA | NPS caves list: 150.4 miles (242.1 km) |
| Clearwater Cave System In Gunung Mulu World Heritage Site. | 236.8 kilometers | Sarawak, Malaysia | Wikipedia longest caves: Clearwater 236.8 km |
| Fisher Ridge Cave System Partly within Mammoth Cave park area. | 209.2 kilometers | Kentucky, USA | Wikipedia longest caves: Fisher Ridge 209.2 km |
About this converter
Mammoth Cave runs 685.6 km, almost 200 longer than Ox Bel Ha at 496.8. Ox Bel Ha in Mexico is the longest underwater cave. Shuanghe in China at 417.7 is the longest in Asia and third overall since 2023. Sac Actun at 376.7 and Jewel at 354.6 follow. Wind at 268.8, Optymistychna at 264.6, Lechuguilla at 242.1, Clearwater at 236.8 and Fisher Ridge at 209.2 close the top 10. Lengths count mapped passage, not depth, and grow as survey teams push new leads each year.
How to use it
Pick two caves and a unit in the top row. The three boxes below stay linked. Change any box and the other two update. Try Mammoth against Jewel to see the near double gap. The bars below scale to Mammoth so the 200 km group looks short. Switch the unit to miles for US figures. Ratios are exact divisions of the mapped lengths.
Mapped length moves yearly. Mammoth is cited at 663.1 in older NPS tables, 685.6 in 2022 surveys and 686 in park articles. We use 685.6 from the 2022 survey. Jewel moved from 335.6 to 354.59 by July 2025. Wind moved past 268.8 in 2024. Underwater systems like Ox Bel Ha and Sac Actun change when divers link new tunnels. Figures here use the latest published survey per source.
FAQ
What is the longest cave?
Mammoth Cave at 685.6 km in Kentucky. The Flint and Mammoth systems linked in 1972.
What is the longest underwater cave?
Sistema Ox Bel Ha at 496.8 km in Mexico. Sac Actun at 376.7 is second among underwater systems.
How long is Jewel Cave?
354.59 km as of July 2025. It is fifth longest in the world and second in the US.
Do cave lengths change?
Yes. Survey teams add km each year. This page uses 2024 to 2025 surveys and notes older totals where they differ.
Sources
- US National Park Service: Mammoth Cave 426 miles (686 km); Jewel Cave 220.33 miles (354.59 km) July 2025; Wind Cave, Lechuguilla 150.4 miles (242.1 km), park resources table
- Showcaves statistics: Longest Caves (Mammoth 685,581 m 2022; Ox Bel Ha 496,804 m 2024; Shuanghe 417,696 m 2024; Sac Actun 376,700 m 2021; Jewel 354,860 m 2024; Wind 268,808 m 2024; Optymistychna 264,576 m 2021)
- Wikipedia: List of longest caves (Mammoth 685.6; Jewel 354.59; Wind 270.5; Lechuguilla 244.8; Clearwater 236.8; Fisher Ridge 209.2 km)
Last verified: 2026-10-09 · 10 entries
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