An unusual event occurred in Montana today: the state legislature went into session.

The wonderfully rococo state capitol building on a hillside in a residential neighborhood here was alive with politics and ceremony as Montana's 49th Legislature took the oath of office, elected its leaders -- and quickly got down to work.

There wasn't much time to spare for partying and celebrating because any legislation not finished by April 4 will have to be put off until 1987. The people of Montana allow their lawmakers to meet for only 90 days every other year.

"And there're a lot of people here who think it ought to be two days every 90 years," said Ted Schwinden, the casual, unprepossessing farmer who began his second term as governor this morning.

As befits the chief executive of a low-key, neighborly state government, Schwinden has his home number listed in the telephone book -- (406) 442-1262 -- and chats with callers day and night.

I called the number last weekend, and when a deep, friendly voice answered, I asked to speak to the governor.

"You are," Schwinden replied.

I asked if I might drop in for a visit sometime today.

"Monday? No problem," the governor replied. "I'm being inaugurated in the morning, but other than that it's not a bad day."

If this tableau suggests a detached, unawed attitude toward government, that's exactly how the people of Montana like to view themselves. They feel, as Schwinden said in his four-minute inaugural address this morning, that government should be as "unobtrusive as a good neighbor."

Yet for all the detachment, for all the resentment of big government and its taxes, laws and intrusions, the people of Montana, like their peers elsewhere in the Rocky Mountain West, are in many ways as closely tied to government as any resident of Washington, D.C.

The two biggest employers in this huge state are the state and federal governments. The two governments are the biggest landowners, and maintain the largest payrolls in the state.

When huge portions of Montana were destroyed by forest and prairie fires last summer, the federal government did most of the firefighting; this was only fair, because Washington owned most of the land that burned. As soon as the fires were out, Helena wrote to Washington asking for federal disaster relief in the form of grants and low-interest loans.

"There's an animosity toward the federal government because of an increasing inability to have any effect on it," Schwinden said. "But still, we want those grants and that big payroll."

As evidence of the conflict, Schwinden cites the 55-mph speed limit, widely viewed here as the narrow-minded imposition of easterners who have no feel for places like Montana, where you can drive in a straight line the distance from Boston to Richmond without leaving the state.

"One of the things you'll hear in this legislative session," Schwinden said, "is a lot of rhetoric about 55. People'll stand up and say Washington should take its regulation and stuff it.

"But in the end, nothing'll happen, you know, because if you change the speed limit you lose the federal highway money -- and we can't stand that sanction."

The Montana Highway Department is the state government's largest bureaucracy. It gets approximately $120 million annually -- about 90 percent of its construction budget -- from the federal government.

Still, the people of Montana generally feel they know more about their lives than does any government official. To accommodate that view, the state goes out of its way to let people keep an eye on government.

Like the U.S. Congress and some other legislatures, Montana has a central computer to keep track of the progress of each bill. Unlike those other legislatures, Montana keeps its computer files open; any citizen with a computer and modem can dial in and read.

The Helena newspaper has a regular feature, "There Ought to Be a Law," inviting readers to write in and propose legislation. Several of the ideas have been enacted verbatim by the legislature in its biennial sessions.

Every legislator lists a home telephone number in the newspaper so constituents can call.

According to the National Conference of State Legislatures, Montana is one of eight states (the others are Arkansas, Nevada, New Hampshire, Kentucky, Oregon, North Dakota and Texas) that permits legislative sessions only every other year.

"Actually, we changed the constitution in 1972 to make it an annual session," Schwinden said today. "But the people were so appalled when they saw how much was going on that they switched it back by referendum real quick.

"The basic attitude is, 'These guys do enough damage every other year. You let 'em meet more, it will just encourage 'em.' "