Mammoth Cave National Park is around the same size as Martha's Vineyard.

Martha's Vineyard is approximately 227 km² (87 sq mi), while Mammoth Cave National Park is approximately 219 km² (84 sq mi), making Mammoth Cave National Park 96.47% the size of Martha's Vineyard.
Tip: This to-scale comparison of Martha's Vineyard vs. Mammoth Cave National Park uses the Mercator projection, which distorts the size of regions near the poles.

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