Katmai National Park and Preserve is at the northern end of the Alaska Peninsula on Shelikof Strait. It comprises Katmai National Park, which measures 1,487,664 hectares (3,674,530 acres) and an adjoining preserve of 169,514 hectares (418,699 acres). The park was established in 1918 as a national monument. It was later expanded and was designated a park and preserve in 1980.

The volcanoes of Mount Katmai and Novarupta, as well as the Valley of the Ten Thousand Smokes, are located in the park. In 1912, Novarupta was the site of one of the greatest volcanic eruptions in history. All plant and animal life in the area was destroyed by the ash and lava, although no people were reported killed. As a result of that eruption, Kodiak Island, which is 160 km (100 miles) to the southeast, was covered with some 30 cm (1 foot) of ash. As lava beneath Mount Katmai drained westward to Novarupta, Katmai's top collapsed, forming a crater of 12.8 km (8 miles) in circumference and 1,128 m (3,700 feet) deep, in which a lake has formed.

The Valley of the Ten Thousand Smokes covers 186 km² (72 sq miles). It features countless holes and cracks through which hot gases used to pass to the surface. Nowadays, all but a few have become extinct.

Katmai National Park includes glacier-covered peaks, crater lakes, a coastline with dramatic fjords and waterfalls, dense marshlands and heavy forests with a variety of wildlife, notably moose and grizzly bears. The park is in the south of Alaska, 1170 km southwest from Juneau and 5590 km northwest from Washington D.C.