President Carter yesterday used his executive authority to designate 56 million acres of Alaska wilderness as federally protected national monuments.

The action, which more than doubled the size of the national park system, affects an area eight times larger than the state of Maryland.

"Because of the risks of immediate damage to these magnificent areas, I felt it was imperative to protect all of these lands," Carter said. "These areas contain resources of unequaled scientific, historic and cultural value, and include some of the most spectacular scenery and wildlife in the world."

Carter's action came six weeks after the massive Alaska lands bill failed to pass Congress because of a last-minute filibuster threat. On Nov. 16, Interior Secretary Cecil D. Andrus withdrew 110 million acres from development for three years under an emergency provision of the Federal Land Policy and Management Act.

However, the 1906 Antiquities Act, under which President Carter acted yesterday, gives the land permanent protection and affords a stronger legal barrier to development, Interior officials said.

The state of Alaska and the Citizens for Alaska Lands, an industry group, had sued Carter to prevent him from designating any Alaskan monuments. Administration officials expect a major legal battle over the land, which the state and mining and oil companies would like to be kept open to development.

The president said yesterday that passage of an Alaska bill by the next Congress "is the highest environmental priority of my administration." Carter has proposed setting aside 92 million acres in parks and wild life refuges, almost a third of the state.

The bill has aroused national controversy; hundreds of citizens and environmental groups favor the parks, while the oil industry, mining companies, and Alaska officials vigorously oppose them.

"In Alaska," Carter said, "we have a unique opportunity to balance the development of our vital resources required for continued economic growth with protection of our natural environment. We have the imagination and the will as a people to both develop our last great natural frontier and also preserve its priceless beauty for our children and grandchildren."

The 17 national monuments designated yesterday cover vast roadless mountain ranges, forests, glaciers and plains where man has hardly trod. Wildlife is more plentiful than anywhere in the nation. Brown bears, caribou, dall sheep, walrus and polar bears abound.

The new monuments include:

The 5.8 million-acre Noatac River basin, the nation's largest pristine river valley.

The 2.6-million-acre Bering Land Bridge area, where man may have first crossed into the new world from Siberia.

The 11-million-acre Wrangell-St. Elias mountain range, with the highest collection of snowy peaks in North America and a glacier the size of Rhode Island.

Admiralty Island in the southeast Alaska rain forest, with 500 bald eagle nests and more bears than anywhere else.

The 10.6-million-acre Yukon flats, where 2.1 million ducks and thousands of water fowl migrate each year.

A 4 million-acre addition that would triple the size of Denali, the park around Mt. McKinley, the nation's highest peak.

Also, the Aniakchak Caldera, one of the world's largest dry volcanoes; Cape Krusenstern, an archeologically rich beach on the Chukchic; and the spectacular scenic areas of Kenai Fjords, Lake Clark, Glacier Bay, Gates of the Arctic and the Kobuk.

Of the 17 national monuments, 13 would be administered as parks, prohibiting sport hunting, roads, mineral development and human settlement. Two would be administered as wildlife refuges and two as national forests, allowing very restricted mineral exploration and hunting.

In addition to the 56 million acres of monuments, Carter said yesterday, the administration will take steps to designate another 40 million acres as permanent wildlife refuges, after public hearings and an opportunity for congressional veto.

Environmentalists had wanted Carter to designate more than 100 million acres as monuments. However, Andrus said that would provide more protection than contemplated in the bill and would result in more litigation.

Alaskan officials are furious at Interior's delay in granting them title to lands they claim under the 1959 Statehood Act. Specifically, they covet 9 million acres that the administration wants for parks. The Yukon flats, for example, should be open to agriculture, state officials say.

While 146 congressmen, led by Rep. Morris Udall (D-Ariz.), had called on Carter to designate the monuments, Sen. Mike Gravel (D-Alaska) yesterday called the action "politically motivated." No rush to development is imminent, and the land is already protected adequately, he said.