Glacier National Park. Celebrating the 75th anniversary of one of America's most unspoiled parklands

HERE in northwestern Montana, among the quarried remains of ancient glacial forces, the last 75 years seem like the blink of an eye. But that snippet in time has been critical for this area, say National Park Service officials, who this year are celebrating Glacier National Park's 75th anniversary.

The park, with impossibly blue glacial lakes ringed by jagged walls of rock, was set aside for protection by Congress in 1910, primarily because of its beauty.

But today, the importance of protecting this area reaches far beyond aesthetics or recreation, says Alan O'Neill, assistant park superintendent.

The park is now understood to be part of an intact world ecosystem, and must not be managed as an island. In fact, the park merges with the Canadian Waterton National Park, and the combined area is officially called the Waterton-Glacier International Peace Park.

This area is a part of the Rocky Mountain corridor stretching from Alaska through Mexico -- a geographical corridor that was established before man set up his economic and political boundaries. ``It's symbolic to look at the resources jointly and manage them as one ecosystem,'' Mr. O'Neill says.

The 1,580-square-mile park has a number of distinctions. In the fall it has the largest concentration of bald eagles in the continental United States. On the Apgar Bridge in West Glacier, visitors can watch hundreds of them swoop down on the Flathead River to grab salmon.

The average tourist here is also virtually assured of glimpsing reclusive mountain goats and sheep. And it's the only park in the Western Hemisphere with headwaters that flow ultimately into the Arctic, Atlantic, and Pacific Oceans.

And the park averages one grizzly bear per 8 square miles -- the largest concentration of the endangered animal in the Lower 48.

Although Glacier National Park is known to be less commercialized than other national parks, it nonetheless faces some of the same development-related issues. Commercialization is at the heart of the debate over protection of the grizzly here, and park officials are battling a proposal to develop a coal mine six miles outside the park in British Columbia.

The park in 1976 was named a Biosphere Reserve under a United Nations program that designates ecologically pure areas and studies man's long-term impact on them. In addition, the park has been nominated for the World Heritage List, UNESCO's 187-site roster of the world's finest cultural and natural locations.

``When we look at 75 years, we're really reflecting on how park management has changed and how we're going to keep the park in the condition you now see it,'' O'Neill says.

Today, park-service management is pretty much hands-off. But in the early days, workers tried to extinguish all natural forest fires and to shoot ``bad'' animals like mountain lions, grizzly bears, coyotes, and wolves to protect ``good'' animals.

The area has accumulated a rich history during its 75 years as a national park, says Clyde Lockwood, the park's director of interpretation. He tells the story of the time President Franklin D. Roosevelt broadcast one of his fireside chats from here.

Plans to celebrate the park's anniversary will recall some of its modern history. There will be a summer full of programs with old-timers who worked to build the spectacular Going-to-the-Sun Road.

The Going-to-the-Sun Road, finished in 1932, snakes along the bottom of a glacially carved thin wall of sedimentary rock that juts jaggedly skyward. To swing around a bend in the Going-to-the-Sun Road, catching the first glimpse of the massive ``Garden Wall,'' is perhaps the park's quintessential breathtaker. The road winds right through rock, snow-fields, and waterfalls that splash, in places, onto the roadway.

Others on hand for this summer's celebration helped to build Swiss-style chalets and grand hotels here in the early 1900s for Great Northern Railroad. The fancy accommodations were for wealthy dudes from Chicago and New York, whom Great Northern shipped in for sightseeing in the West. Former pack-horse guides who took the city tourists from hotel to hotel will be giving talks in the park this summer.

In addition, a park interpreter will portray the late George Bird Grinnell, founder of Field and Stream magazine, who first suggested that this glacially carved terrain be protected as a national park.