A head house is an enclosed building attached to an open-sided shed.
In the 18th and early 19th centuries, head houses were often civic buildings such as town halls or courthouses located at the end of an open market shed; one example is the former market and firehouse from which Philadelphia's Head House Square takes its name.
In mining, a headhouse is a structure enclosing the entrance to an underground mine.
Since the mid-19th century, head house is most commonly encountered as an American railroad term for the part of a train station that does not house the tracks and platforms. Outside America, the same part of a station is known as the station building.
In the context of rail transport, head house usually refers to the portion of a large passenger terminal that contains the ticket counters, waiting rooms, toilets and baggage facilities. It might also include the passenger concourses and walkways between the platforms and other facilities. The head house at Philadelphia's Reading Terminal, which fronts a two level shed with tracks and platforms placed above a covered market, combined both the older and newer meanings of the word.
Larger terminals had amenities that were contained within their own distinct building, which was separate to the railroad. For instance, when Cincinnati Union Terminal opened in 1933, the head house held a restaurant, lunch room, ice cream shop, news agent, drug store, small movie theater, men's and women's lounges, and restrooms that included changing rooms and showers.
In the context of subways, a head house refers to the part of a subway station that is above ground, which may be nothing more than a covered entrance. The head house may contain escalators, elevators and ticket agents.
On the New York City Subway, a head house is referred to as a "Control House". They were built, and are still used in certain locations, where a simple staircase or kiosk was not desirable. During the design and construction of the city's original IRT system (opened 1904), control houses were as treated as integral architectural features of the system. In 1901, William Barclay Parsons, chief engineer for the Board of Rapid Transit Railroad Commissioners, had traveled to Boston with architect Christopher Lafarge, where he was apparently inspired by the ornamental houses he saw used as entrances on the Tremont Street Subway. In response, architects Heins & LaFarge designed each IRT control house to be an attractive, exterior feature of the transit network system that was in keeping with its location. The buildings, which are examples of the Beaux-Arts style, are similar to other ground-level structures on the IRT, such as the powerhouses and sub-stations.