As leader of the nation's most affluent county, Kate Hanley was expected to live the suburban dream. Her house on Camp Alger Avenue in the Falls Church section of Fairfax was a classic split-level, patch of yard, kids all around.

It was the perfect place for the Hanleys -- Kate, husband Ed and their two kids -- and its location in the center of the county worked nicely as Kate moved up in politics from School Board to Board of Supervisors.

Don't look now, but Hanley has put the house/garage/lawn model of life in her past. First elected a supervisor in 1986 as part of a voter rebellion against the fast pace of development and the urbanizing of suburbia, Hanley now lives in downtown Reston -- in an apartment tower at the core of the new Fairfax, in a place with sidewalks, pedestrian-oriented retail and tall buildings that cast long shadows.

Leaving politics last year liberated Hanley to live how and where she wanted to.

It's not that she disliked the life in Falls Church. Hanley says she and Ed, now retired from federal work, picked that neighborhood because they "just wanted the kids to be able to get places on their own. They could walk to the library and the pool and the rec center." Hanley herself didn't make much use of the area's amenities: "My idea of an outdoor event is a sidewalk cafe."

But the 1960s suburban ideal was pretty much the only model back when Hanley moved into her old house. And when she switched careers from teacher and guidance counselor to politician, her instinct was to appeal to the popular desire to hold the line against voracious developers.

After all, Fairfax's population had jumped from 600,000 to 700,000 in the first six years of the '80s, and residents had had enough of the congestion and crowding. "There was a feeling then that building tall wasn't right for a suburb," she recalls.

But in the two decades that followed, as the county's population topped 1 million, suburbia developed its own version of the city, and as board chairman, Hanley played a big role in shaping the town centers and urban clusters that now dot the county.

Then, a few years ago, she broke her heel and spent Christmas crawling on her knees up and down the stairs of her house. "And I realized my next home was going to be one story," she says.

Hanley had watched Reston Town Center from its conception. She went out to look at an 11th-floor apartment and loved it.

So now she walks five blocks from home to her job as director of the Greater Reston Arts Center, which sponsors exhibitions, classes and other visual art events. She's one block from a library and a bookstore, and a few more steps from a selection of eateries.

"Here's the measure of quality of life," says Ed Hanley. "We have three Starbucks within a seven-minute walk."

From the Hanleys' terrace, you can see all the way to Sugarloaf Mountain in northern Montgomery County and out to the Blue Ridge.

In her new routines, Kate Hanley has discovered the appeal of density, whether she's ducking in at Starbucks on her walk to the office, people-watching along Market Street or deciding where to dine each night (Hanley takes pride in her decision never to learn to cook).

Having fallen out of touch with her old neighbors, she rarely looks back at her home of the previous 22 years.

Reston Town Center has been criticized from the start as something artificial, a couple of faux-urban blocks plopped in the middle of suburbia -- tall office buildings and condos surrounded by fields of parking.

"Is it like a downtown of a city? No," Hanley says. "But it's a 21st-century iteration of something different. I had to stay in Fairfax; I was still the chief elected officer when we bought here. And it does still look like a movie set, but more buildings are going up, and that feeling will fade."

Twice each day, Hanley gets a frightening reminder that she still lives in a very car-oriented place, as she gambles her life and jogs across the six lanes of Reston Parkway that separate her home from the town center.

That experience also connects the recovering politician with her former life: "You'd be amazed at the number of people who come up to me and say, 'Kate, I almost ran you over on Reston Parkway!' "

This is one in a series of columns in which people explain why they live where they live.