Which U.S. national park, established in 1872, is the world's first national park and a World Heritage Site?

The U.S. national park established in 1872 and recognized as a World Heritage Site is Yellowstone National Park.

President Ulysses S. Grant signed the Yellowstone National Park Protection Act on March 1, 1872. The law set aside Yellowstone as a public park, making it the first national park in the United States and the park most widely recognized as the world’s first national park.

Yellowstone is famous for a landscape shaped by volcanic activity. It contains geysers, hot springs, mud pots, colorful pools, deep canyons, forests, and large populations of bison, elk, bears, and wolves. Old Faithful is its best-known geyser, although it is only one feature within a much larger geothermal system.

UNESCO designated Yellowstone a World Heritage Site in 1978 because of its outstanding geothermal phenomena, scenery, ecosystems, and wildlife. Banff, Yosemite, and Grand Canyon are also celebrated national parks, but they were established later or do not match the question’s 1872 clue.