That vast land way beyond the Capital Beltway described by Washingtonians as the Great Out There is rapidly becoming a part of us. Places as faraway-sounding as Washington County and Spotsylvania could become as commonplace for commuting as Fairfax and Silver Spring. And by the year 2000, the Washington and Baltimore metropolitan areas could be rubbing shoulders.

Those are among the projections that can be drawn from a new study by the Metropolitan Washington Council of Governments (COG) that shows the Maryland fringe areas are experiencing "significantly more growth" than their Virginia counterparts in the decades leading up to the year 2000. Anne Arundel County, already home to many Washington workers, is projected to grow to nearly a half-million people and become by far the largest of the outlying jurisdictions.

The new COG survey appears to support the trend revealed in earlier studies showing the Washington metropolitan area expanding outward during the next two decades, with for example, Anne Arundel, whose orientation has been toward Baltimore, becoming a Washington suburb.

"We're highly impacted by both the Washington metropolitan area and the Baltimore metropolitan area," said Florence Beck-Kurdle, director of the Anne Arundel County Office of Planning and Zoning.

She said most of her county's Washington suburban growth is concentrated along the Rte. 50 corridor between Washington and Annapolis.

"It goes all the way to the Bay Bridge, and maybe even farther," she said. "They are very Washington-oriented people there. There's much more of a Washington-bedroom aspect to it." She said a county government study showed that many people buying their first home in Anne Arundel were Prince George's County apartment dwellers.

The new study also raises questions as to whether these outlying jurisdictions will be prepared to handle this expected rapid growth. On Monday, Anne Arundel officials were forced to declare a moratorium on building permits in the northeastern part of the county around Glen Burnie, when it was discovered that more building permits had been approved than the Cox Creek sewage treatment plant could handle.

The Council of Governments, which issues periodic reports on growth and trends in the region, is generally considered authoritative by area analysts, despite being caught up, as were most demographers, in overly optimistic growth projections in the 1960s.

The new COG survey concludes that by 2000, Washington's fringe jurisdictions--stretching from Spotsylvania in Virginia to Washington County in Western Maryland--are expected to grow by more than 400,000 people, a 40 percent increase over their 1980 populations.

"Housing is cheaper, jobs are developing out there, and more industry is locating there," said demographer George Grier, a consultant to the Greater Washington Research Center.

"They're moving to the fringe from the city; they're moving from the inner-suburbs to the outer-suburbs, and people are moving there from outside the region," he said.

But most of those moving to fringe areas will commute to the Washington suburbs, not to the District of Columbia itself, for employment, according to demographers.

"They by-and-large won't work downtown, they'll work in the suburbs," said Atlee Shidler, executive vice president of the nonprofit Greater Washington Research Center, which has also studied growth in the fringe areas.

"The suburbs have created their own suburbs, in a sense," he said. "They work on the edges. They work along I-95. They work along the I-270 corridor. It's very easy to live in Frederick County if you work in upper Montgomery."

The Maryland fringe is considered to be Anne Arundel, Calvert, Charles, Frederick, Howard, St. Mary's and Washington counties. The Virginia fringe consists of Clarke, Fauquier, Frederick, King George, Stafford and Spotsylvania counties, and the cities of Winchester and Fredericksburg.

As a sign of the growing importance of the fringe jurisdictions, two Maryland and one Virginia fringe counties--Calvert, Frederick and Stafford--are all being included in the Standard Metropolitan Statistical Area, which is the officially designated Washington metropolitan area.

The Virginia fringe jurisdictions are expected to have a larger population increase over the next 17 years, growing by 48 percent to 298,000. But Maryland's fringe counties, despite a lower percentage rise of 38.7 percent, will continue to have a larger population. Maryland's fringe counties are expected to grow to a total of 1.2 million people.