Yosemite National Park is about 3 times smaller than Yellowstone National Park.

Yellowstone National Park is approximately 8,983 km² (3,469 sq mi), while Yosemite National Park is approximately 3,027 km² (1,169 sq mi), making Yosemite National Park 33.7% the size of Yellowstone National Park.
Tip: This to-scale comparison of Yellowstone National Park vs. Yosemite National Park uses the Mercator projection, which distorts the size of regions near the poles.

Compare further: Yosemite National Park vs. Yellowstone National Park

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