Established: In 1872, legislation was passed making Yellowstone the world's first national park.

Land Area: 2.2 million acres of forests (80 percent), grassland (15 percent) and water (five percent). Although 96 percent of Yellowstone is claimed by Wyoming, small portions of the park also lie in Montana (three percent) and Idaho (one percent).

Lowest and Highest Elevations: 5,282 feet at Reese Creek to 11,358 feet at Eagle Peak's summit.

Number of Plant and Animal Species: Seven species of conifer trees, more than 1,000 species of native flowering plants, 61 mammals and 320 bird species.

Popular Sights: Yellowstone's geysers and hot springs such as Mammoth Hot Springs and Norris Geyser Basin, Yellowstone Lake, waterfalls such as Upper and Lower Falls, Gallatin Range, Hayden Valley and Old Faithful.

Popular Activities: Enjoy free ranger-led programs, sightseeing tours, fishing, boating, cross-country skiing and horseback riding in the park.

Hiking: There are more than 950 miles of backcountry trails. Roads and facilities take up less than three percent of the park; the rest is wilderness.

Visit www.TravelYellowstone.com or www.nps.gov/yell.