The quest for a home in the suburbs pushed many small commuter towns into the ranks of the nation's fastest-growing cities over the past decade, according to 1990 census figures released yesterday.

Many are in the Southwest, which has grown dramatically as population has shifted away from the Midwest and Northeast. Boom towns such as Rancho Cucamonga, Calif., and Mesquite, Tex. -- little-known outside their states a decade ago -- have moved ahead of Youngstown, Ohio and Roanoke, Va. as population centers.

Among the 10 big cities making the greatest gains in the last decade, all but two were situated on the edge of a major urban center, most often Los Angeles. And the two non-suburban communities among the fastest gainers -- Bakersfield and Fresno, Calif. -- attributed much of their growth to the spillover from the massive Los Angeles and San Francisco Bay areas.

"People hope to leave behind them the strains and stresses of urban life, the problems of pollution, the problems of traffic," said Alan Heslop, professor of government at Claremont McKenna College in California.

But unlike the story of American suburbanization in the 1950s, the experience of the past decade may have proved disappointing, he said.

"People found that the traffic was following them, and the growth began to present them with many of the problems they thought they'd left behind."

The Census Bureau, in reporting statistics for the nation's cities with populations of more than 100,000, said two were not even incorporated in 1980: Santa Clarita and Moreno Valley, Calif. Both typify what demographers and sociologists have begun to call "exurban" growth, the leapfrog movement of young families 30 miles or more outside a big city.

In the case of Santa Clarita, a valley 50 miles north of Los Angeles, four small communities incorporated as a city in 1987 in an effort to stem what residents there saw as undesirably rapid growth.

"It was out of control," said Jan Heidt, a member of the city council. "All this growth took place on the same infrastructure we had had for years."

The fastest growing city in the nation was Mesa, Ariz., a community outside Phoenix, which grew 89 percent to 288,091. The second fastest was Rancho Cucamonga, a suburb of Los Angeles, which grew by nearly 84 percent to 101,409.

Among the nation's largest cities, the fastest growth was also in the south and west. Houston displaced Philadelphia as the fourth largest city and San Diego, which grew nearly 27 percent, moved ahead of Detroit and Dallas. The top 10: New York, Los Angeles, Chicago, Houston, Philadelphia, San Diego, Detroit, Dallas, Phoenix and San Antonio.

Five cities fell below the 100,000 mark: Roanoke, Columbia, S.C., Davenport, Iowa, Pueblo, Colo., and Youngstown.

The attraction of medium-sized cities in or near major metropolitan areas was not exclusive to the Sun Belt, but also true in midwestern and northeastern communities, including Detroit and New York City. The population increase in these suburban communities also stems from the inability of many of the nation's big cities to accommodate more growth.

"It's next to impossible for Boston, New York, Washington, Baltimore or San Francisco to change their populations very much because their boundaries are so narrow," said Calvin Beale, a demographer at the Agriculture Department. "You just can't keep increasing the density per square mile. It's got to sprawl."

Beale also assigned part of the growth of the southwestern communities to immigration. In some cases, he said, suburbs have annexed new developments, boosting their populations dramatically.

Overall, the nation's largest cities fared slightly better in the 1980s than they had in the 1970s, Beale said, both economically and by stemming population loss.