iIn an age before high-rise apartment buildings and easy transportation, cities from New England to the mid-Atlantic states faced a challenge: how to house rapidly growing populations close to places of work and the necessities of urban life. The solution proved both elegant and enduring—the unassuming row house. Today, this adaptable housing form continues to lend its distinctive charms to residential streets up and down the Northeast Corridor.

Fundamentally, a row house is a building that stands cheek by jowl with its neighbors, often sharing a common wall. Although purists insist that only houses built contemporaneously should properly carry the label, others broaden the definition to include adjacent structures of similar style and dimensions. As a rule, row houses generally rise no higher than five stories.

Within these broad guidelines, row houses can vary a great deal in size, design and construction, from city to city and within a single municipality. A given city’s signature style often reflects the ready availability of certain materials—such as the marble from the nearby Texas, Md., quarry that gives Baltimore’s row houses their celebrated white steps or the New Jersey sandstone that coats New York’s brownstones.

Similarly, di erences in row house design can yield clues to changing patterns of usage. Ed Mauger, founder of Philadelphia on Foot tours and author of Philadelphia Then and Now, points to the single front steps of pre-Revolutionary row houses as artifacts of a time when merchants and artisans lived above their first-floor stores and workshops, which benefited from easy access to the street. With the advent of the Industrial Revolution, however, men began to travel outside the home to work, and the number of steps was increased to afford greater privacy for what had become a strictly familial space.

No matter the style, row houses can lend a pleasing order and rhythm to a city block. Their human scale and the sense of continuity they provide