Zion National Park, existing in Springdale, Utah near St. George, began its life as Zion National Monument, centered around the Kolob Arch, the longest natural arch in the world. Later it was expanded and Mukuntuweap National Monument was incorporated into it and the whole big place was declared a National Park on November 19, 1919.
What Zion's (as it's colloquially called) has got is 229 square miles (593.1 km) if space which included the Kolob Arch with a span that measures 310 feet (94.5 m). They used to let you walk across it, but there was fear it would crack from the strain so you have to now be content with going under it.
Hiking. Check. Biking. Check. Camping. Check. Horseback riding. Check. Motorcycle and ATVs? *** BZZZZ *** Not in Zions'. Human powered movement only except on the asphalt roadways. You want 4x4 rock hopping? Try Moab.