Here in Washington, DC, rowhouses are the city's most common housing type. But throughout most of the rest of the United States, they're comparatively rare. This map shows where you'll find them, and where you won't.
How the map came to be
To create the map, I created a publicly-editable Google Map and asked people to drop dots in any city they knew to contain urban rowhouses. Cities with entire neighborhoods full of rowhouses got a red dot, while cities with sporadic rowhouses but not entire neighborhoods got a grey dot.
The crowdsourced data is surely incomplete, and a tad subjective. Some cities with rowhouses are probably missing from the map, and some without may be incorrectly shown. And there could be some variation in what different respondants considered to be "neighborhoods full" versus "sporadic."
Nonetheless, rough boundaries of US and Canadian "Rowhouse Country" are discernable.
Where are the rowhouses?
In the US, the core of Rowhouse Country, where rowhouses are the dominant housing type for large portions of big cities, is a mid-Atlantic triangle roughly from Albany to Pittsburgh to Richmond, centered around Philadelphia. There's a clear tail headed westward from Philadelphia as far as Saint Louis, where a narrow band of midwestern cities are rowhouse rich.
Outside the triangle and its westward tail, most cities fall into the "sporadic" category.
Rowhouses turn out to be surprisingly rare in New England. In the south and west, only a few cities like Savannah and San Francisco have them in great quanities. Chicago does have a lot, but even there most of its "rowhouse" neighborhoods have narrow gaps between buildings, and thus aren't really rowhouses.
On the other hand, a tremendous number of cities have at least a handful of rowhouses, and sometimes they're exotic. Nobody is surprised to see New Orleans on the map, but who expected Colorado?
Help improve the map
Want to help make the map better? Maybe you see a mistake on it, or you know of a city with rowhouses that isn't shown? It's easy to help!
First, please stick to urban attached rowhouses. Don't add suburban townhouses, and don't add detached buildings with narrow gaps between them. One dot per city is adequate; there's no need to add a new dot to any city that's already on the map.
Then, open up the editable Google Map. Either click on existing dots to edit them, or use the "Add marker" tool to drop a new pin in any city you know of with rowhouses. When you edit or drop a new pin, label it with the city name, and in the space below the name type in either "lots" or "few" to indicate whether that city has neighborhoods full of rowhouses ("lots") or only sporadic ones ("few").
Alternatively, feel free to leave a written comment here or on Flickr.
Even if you don't have anything to change on the map, tell us what stands out as interesting!
Thumbnail: Image by the author.