Mt Rainier, a dormant ice-capped volcano that soars to 14,410 feet southeast of Puget Sound, is the highest point in Washington and in the Cascade Range. The summit was first reached in 1870. It has the largest single-peak glacier system in the contiguous states, with 25 named glaciers. Snow and ice cover more than 35 square miles.

The park preserves an area of 235,625 acres, almost all of it protected wilderness. It includes dense old-growth forest, subalpine meadows, and a diverse array of wildlife. Activities include camping, hiking, mountain climbing, fishing, horseback riding, snowshoeing, and cross-country skiing. It is generally cool and rainy, with summer highs of 60\260 to 70\260F. July and August are the sunniest months but rain is possible anytime.

There is a small entrance fee per vehicle that is good for seven days, but this does not include camping fees. Lodging and restaurants are available at Longmire Historic District in the southwest corner and at Paradise.

The park is open year-round, but various facilities are open seasonally. There is no public transport to or in the park, but most roads are open from late May to early October; parking is scarce sunny summer weekends. Year-round access is along State Route 706 to the Nisqually Entrance, in the southwest corner of the park. Limited winter access is available on Hwy 123, in the southeast corner. The Carbon River/Mowich Lake area, in the northwest corner, is accessed via State Route 165 through Wilkeson. Summer access is via Hwy 410 on the north and east sides of the park. The main airport is Seattle-Tacoma International.