Every weekend in Fairfax County, thousands of Buddhists and Baptists, Catholics and Jews and followers of other faiths pray in car dealerships, condominiums, classrooms, garages, fire stations and even tents in a field on Route 7.

The 1980s population boom in Washington's suburbs has been a blessing to religion. Churches and temples cannot be built fast enough to accommodate the record numbers of people joining them, forcing overflow crowds to meet wherever they can.

While churches have grown rapidly in other jurisdictions -- 71 religious groups gather in public schools in Montgomery County, many awaiting the construction of permanent quarters -- the expansion has been particularly rapid in Fairfax County, where the population grew by nearly 200,000 in the 1980s.

Newcomers, however, may not be the only reason for the standing-room-only crowds in churches and temples and the 200 recent applications in Fairfax for new or expanded religious facilities.

In fast-growing suburbs such as Fairfax, where neighbors are often strangers, where the corner store is a giant warehouse and country clubs are out of reach for most, the local place of worship has become a community hub, according to parishioners, ministers and academics.

Branching out beyond bingo and raffles, churches and synagogues now offer aerobics exercise classes, softball, singles nights, job counseling, arts lectures, day care, reading clubs, ski trips and a growing number of other activities.

Churches and temples also continue to play their traditional role as a moral beacon, particularly for parents hoping to expose their children to religious and ethical teachings.

Religious studies classes for children are so popular in Fairfax that more than 100 temporary trailers have been lined up alongside churches and temples, according to religious and county zoning officials.

"It's really a return to the days before the automobile, when churches were the place that boy met girl and church suppers weren't corny," said George Mason University professor N.J. Tavani, who teaches courses on the sociology of religion.

"Especially for people who don't have relatives around or just moved in, it's a way to meet other people," said Shirley Ballard, a parishioner at Fairfax Christian Church who moved from Mississippi two years ago. "It's sort of a family."

Ballard, a schoolteacher, said older women in the parish "get together on Thursdays to socialize; it gets them out of the house." Ballard and other younger members of the Fairfax City congregation meet regularly too, to discuss books and make wreaths and other crafts.

On Wednesday nights in Springfield, Ejoki Buddhist Temple offers classes in Japanese folk dancing and calligraphy. Every other Friday, Messiah United Methodist Church throws a dance for as many as 200 singles. And throughout the week, Northern Virginia Hebrew Congregation in Reston sponsors chavurahs, or gatherings of friends, whose activities range from swimming to sampling fine restaurants.

"More and more of our congregants want" the temple to respond not only to religious needs but to provide a "whole social experience," said Susan Sailer, president of Northern Virginia Hebrew Congregation.

Tavani, the George Mason professor, said the automobile meant people could live in anonymity in the suburbs and drive distances to work and more glamorous places to dance and have dinner than the local church. The downside, though, is a loss of a sense of belonging to the place where people live.

In new suburbs throughout the country, regional malls and strip office and shopping complexes have killed the character of communities, said Ray Oldenburg, author of "The Great Good Place: Cafes, Coffee Shops, Community Centers, Beauty Parlors, General Stores, Bars, Hangouts and How They Get You Through the Day."

Post-World War II zoning laws, he said, created suburbs that "prohibited everything besides single-family homes. Developers just knocked down trees and built house after house, sometimes varying the facade." Churches, one of the few structures allowed in neighborhoods, are now benefiting from their location, Oldenburg said.

"It makes sense that churches are offering a mushrooming number of nonspiritual functions," Tavani agreed. "With real estate costs so high, why not use these buildings that are right there in the neighborhoods all during the week instead of just on Sunday?"

St. George's Episcopal Church in Arlington, which draws members from all over Northern Virginia, is in use every day from 6:30 a.m to 10 p.m., said the rector, the Rev. Robert C. Hall.

He said there are gatherings of alcoholics, overeaters, condominium association members and others: "We have all kinds of meetings. Some are getting together for the company; others are studying the Dead Sea Scrolls."

In Fairfax, religious congregations and their activities are multiplying like the biblical loaves and fishes.

Almost every major thoroughfare in the county has a roadside sign announcing a new church building. Some congregations herald "Double Sunday Services Coming Soon" in local newspapers. School parking lots are jammed on weekends as thousands attend religious services in county classrooms and gymnasiums.

Meeting space is so scarce that different denominations are praying in shifts at the same church building. The B'Nai Shalom Jewish congregation in Burke, for instance, has services in Abiding Presence Lutheran Church on Lee Chapel Road.

Fairfax officials, swamped with building requests, recently began offering a special Friday building regulations seminar especially for pastors and parishioners, dubbed the "Holy Hour."

Since 1987, more than 200 congregations have sought permission for new or enlarged facilities. There were only 275 places of worship in the entire county at the last comprehensive count in 1980.

Sometimes, the building requests are grandiose -- First Assembly of God wants to erect a 2,360-seat church with a towering cross and steeple on Backlick Road. Sometimes they're unusual -- Leesburg Pike Community Church wanted -- and won -- a permit to pray in an open field on Route 7.

"Religion is not dead, contrary to popular belief," said Dean R. Hoge, a sociology professor at Catholic University who has written about the decline and rise of church attendance. In general, he said, "the more children, the more churchgoing."

Religious participation in America peaked in the 1950s, when there was feverish church building in U.S. suburbs. Most congregations suffered declines in membership throughout the 1960s and 1970s. Academic studies and a series of 1989 Gallup polls showed the decline stabilizing in the 1980s.

The polls and studies also indicate that a significant number of baby boomers who had rebelled against organized religion are now returning to it as their children reach school age.

"If it weren't for the kids, I probably would have continued worshiping" the Sunday newspaper, said Marsha Stanley, a member of Fairfax Unitarian Church, one of the largest Unitarian congregations in the country. Born a Protestant, Stanley said she drifted from religion, in part because of its sexist stance toward women, until she found her children asking, "Mom, what religion are we?"

Echoing comments of other parents interviewed, Stanley said that her church's education program "provides a baseline to talk about religious and ethical issues."

Andrew Garlichs, a Treasury Department employee who ushers at the early morning Mass at St. Andrews Catholic Church in western Fairfax, said one of the major reasons he joined the church when he moved here three years ago from New York was to "let my children know how supportive belonging to a church can be."

Garlichs's church -- formed last summer because the established Catholic Church in Centreville grew to 4,000 members -- is awaiting the money and county permission to build its own building.

In the meantime, it meets in the Centreville High School auditorium. It used to gather at the Fairfax Fire and Rescue Department's Co. 17 station in Centreville. "The firehouse was fine," Garlichs said, "but hey, if the alarm went off, you heard it."