Grand Canyon National Park is about 1.9 times smaller than Yellowstone National Park.

Yellowstone National Park is approximately 8,983 km² (3,469 sq mi), while Grand Canyon National Park is approximately 4,863 km² (1,878 sq mi), making Grand Canyon National Park 54.13% the size of Yellowstone National Park.
Tip: This to-scale comparison of Yellowstone National Park vs. Grand Canyon National Park uses the Mercator projection, which distorts the size of regions near the poles.

Compare further: Grand Canyon National Park vs. Yellowstone National Park

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