Spring Valley

In 1929 the Miller brothers did something quietly radical: they set aside the city's grid. Their streets follow the land instead, curving with the hills, and none of them go anywhere except home. The result, a century on, is the closest thing Washington has to countryside inside its own lines. Colonials, Tudors, and Cape Cods sit on a quarter-acre and more, behind lawns rather than walls, under a canopy that reads from the air as forest.

It is a market of single houses, not inventory. A few dozen trade in a typical year, many to buyers who have been waiting for one street in particular, and the neighborhood absorbs them without ever seeming to change.