The AHS does not use the term "townhouse," because it has different meanings in different parts of the country. The AHS classifies housing units on the structural characteristics of the unit and the number of units in the structure. If the structure has unbroken walls extending from the ground to the roof that divide it from adjoining structures, it would be classified as "one unit, attached." Other types of townhouses (for example, stacked) might be classified in the "2 to 4," "5 to 9" or other appropriate category. Units in Structure data is available from the AHS in the General Housing Data table, which is included in the AHS Summary Tables package. It is also in the AHS Table Creator as part of the Units by Structure Type column variable.