Affordability and Montgomery County often seem to be mutually exclusive terms. It's possible to have one or the other, but rarely both.

Twinbrook, fewer than 10 miles north of Washington in the City of Rockville, is one of the exceptions. It was even developed with affordability in mind.

At the end of the 1940s, World War II GIs and their young families flocked to Twinbrook's small frame houses, mostly Cape Cods, when they began popping up on new streets surrounded by farms and wheat fields. The modest houses, developed by builders Joseph Geeraert and Donald Gingery, were constructed with expansion in mind--two bedrooms and one bath on the first floor, with an unfinished upper level, to be finished or added on to as the young couples could afford to do so.

A second area was developed a few years later solely by Geeraert, a Belgian who emigrated to the United States in 1933. With larger lots, Geeraert expanded the Twinbrook repertoire of houses to include split levels, small colonials and ramblers. He incorporated cathedral ceilings, larger bathrooms and spacious kitchens--features unusual enough in the early 1950s that his friends thought him mad.

The wheat fields are long gone, of course--Twinbrook hugs both sides of bustling Veirs Mill Road--but the World War II vintage of the neighborhood is evident from streets named for its military leaders, locales and battles--Bradley, Nimitz, Ridgeway and Patton; Ardennes, Aleutian, Okinawa and Midway.

Some Twinbrook homeowners remember the flavor of those early days.

Rick and Georgia Bentley were making $5,000 a year when they purchased their Twinbrook home in 1949, with help from the GI Bill. The $9,750 house cost them $42.79 a month after a $50 down payment. It was a "temporary" home, said Mrs. Bentley, a twinkle in her eyes. "The wonderful neighbors are what made us stay."

Paul DeShetler, an Iwo Jima veteran now retired from his job as a technical director for ABC News and a Twinbrook resident since 1953, recalled that his friends wondered why he was moving so far out into the country. Chuckling as he contemplates the suburban sprawl that has replaced the wheat fields, DeShetler says he remembers when Congressional Plaza was Congressional Airport, with approaching planes flying so low he felt he could almost touch them from his yard.

The Twinbrook Community Association considers both sides of Viers Mill Road to be Twinbrook, while city records call the northern half Twinbrook Forest. Nonetheless, everyone agrees that the subdivisions use the same services--Twinbrook Library, the Twinbrook Metro stop and the two Twinbrook shopping centers.

The physical difference in the two neighborhoods was apparent to a child's eyes. Judy Tolbert, a resident since she was 10, now lives with her husband, Bob, in his boyhood home, also in Twinbrook. "We lived on the 'poor' side," she said. "The people across Veirs Mill were on the 'rich' side--but we were the real Twinbrook."

Today, sitting on the cheerfully decorated porch of her meticulously landscaped property, she laughs at those perceptions from long ago. She confesses to a feeling of wanderlust, but notes that "many of my friends' parents still live here, so I get to keep the contacts. My best friend's mom lives next door."

Patti Timm remembers Twinbrook post-airport and pre-shopping center, when one of the airplane hangars became the neighborhood roller-skating rink. Baby boomers flourished in the Twinbrook of the 1950s and '60s. Timm had eight siblings. The DeShetlers and the Bentleys each had seven children. It wasn't unusual to find 50 or more kids living within a few blocks of one another. Parents would usher children out the door in the morning and not see them until suppertime.

Today's Twinbrook is quieter. While many of the original youngsters, like Patti Timm, have returned to raise their own families, the families are smaller, and societal changes have reined in a child's freedom to roam.

As one of the lowest-cost neighborhoods in Montgomery County, Twinbrook is a magnet for first-time homeowners and for investors, who rent out the small houses. Both groups present a challenge to the Twinbrook Community Association, according to association President Randy Gentry.

Gentry and the association are working with the City of Rockville to develop a packet of information for new homeowners, enumerating community expectations and resident responsibilities. The city has also created numerous programs--such as the Free Paint Program--to help lower-income families rehabilitate their properties.

Teaching new homeowners and renters their responsibilities, Gentry said, is better than berating them for not living up to expectations. "TCA is a community association, not a homeowners association," said Gentry. "Our job is to identify the needs of the community and find a solution."

New non-English-speaking residents present further communication challenges. Communication and property maintenance have risen to the top of the association's priority list.

Jane Fairweather, who has her own real estate company, and who used to own investment property in Twinbrook, said the association is seeking a workable balance between residents' freedom to do with property as they wish, and an association's natural desire to mandate community preferences.

Phil Gerken, a veteran real estate agent with Weichert Realtors, sees the growing Neighborhood Watch program as a big factor in helping to foster the "neighborly side of life."

As Twinbrook gets ready for its 50th anniversary celebration--set to coincide with the opening of the new community center on Oct. 16--efforts are increasing to make residents of all 3,000 houses feel part of the neighborhood. Carol Hannaford, the association's secretary, quit her position with the city's Human Rights Commission to devote more time to the outreach effort. Both she and Gentry are seeking to broaden ethnic representation on the association's boards. "I'm very pleased with the relationship Twinbrook has with the city--we are helping each other," she said.

Just as some of the homeowners have changed, so have many of the houses. Many residents have raised roofs, added porches and other living spaces, and creatively landscaped their grounds. But it's neighborliness and convenience that have kept people in these "starter" homes decade after decade. Gentry knows that with a little effort on everyone's part, those qualities will continue to be the hallmark of the Twinbrook community--on both sides of the Veirs Mill divide.

Let us know about your little corner of ever-greater Washington and maybe we'll tell everyone. Write to Where We Live, Washington Post Real Estate Section, 1150 15th St. NW, Washington, D.C. 20071. Or e-mail us at where@washpost.com.

BOUNDARIES: 3,000 houses between Twinbrook Parkway and Rock Creek Park to the east, Metro tracks to the south, Baltimore Road to the north

PROPERTIES SOLD: 25 houses sold in the past 12 months ($90,000 to $175,000); 11 houses now on the market ($120,000 to $199,000)

SCHOOLS: Twinbrook and Meadow Hall elementary, Julius West and Earle B. Wood middle, and Richard Montgomery and Rockville high schools

WITHIN WALKING DISTANCE: Rock Creek Park, Twinbrook Metro, Twinbrook Library (closed for renovations), Twinbrook Shopping Center

10 TO 15 MINUTES AWAY: National Institutes of Health, White Flint Mall, Strathmore Hall, Lake Needwood

50TH ANNIVERSARY CELEBRATION: Saturday, Oct. 16, 10 a.m. to 5 p.m. at the new community center, 12851 Twinbrook Pkwy., Rockville. Gymnastics demonstrations, food, and outreach activities are planned.