I did not really plan on visiting this park. Just happen to be in the way between Las Vegas, NV and Page, AZ to see the Lower Antelope Canyon. Below are some facts I lifted from the brochure issued by the National Park Service that I got after paying the park entrance fees.
Established as Mukuntuweap National Monument in 1909 and was expanded in 1919 as Zion National Park. Kolob Canyons section was added in 1937. Current size is 229 square miles.
The name Zion, a Hebrew word referring to a place of safety and refuge, was given to this canyon by Mormon pioneers in the 1860s. Kolob, in Mormon theology, is a heavenly place close to God.
Evidence of Ancestral Puebloans date from about 2,000 years ago; Southern Paiutes from 800 years ago. Mormon settlers arrived in the 1860s. Visitation in 1920 was 3,692; in 1997, 2.5 million.
Tunnel Limitations: The Zion-Mt. Carmel Tunnel is between the East Entrance and Zion Canyon. It was built in the 1920s when cars were small and few in number.