The tobacco barn, a type of functionally classified barn found in the USA, was once an essential ingredient in the process of air-curing tobacco. In the 21st century they are fast disappearing from the landscape in places where they were once ubiquitous. The barns have declined with the tobacco industry in general, and U.S. States such as Maryland actively discourage tobacco farming. When the US tobacco industry was at its height, tobacco barns were found everywhere the crop was grown. Tobacco barns were as unique as each area in which they were erected, and there is no one design that can be described as a tobacco barn. History The terminology "tobacco barn" has been used to describe myriad structures in the USA. Buildings used for strictly tobacco curing, buildings that have multiple agricultural uses, and dilapidated barns, among others, have all been called tobacco barns at one time or another. In the Connecticut River Valley (Tobacco Valley) which extends through Connecticut, Massachusetts and up to Vermont, the curing "barns" are properly called "sheds" (tobacco sheds). The term "barn" is exclusively used to refer to structures that house livestock in this area (New England). When referring to any tobacco operation in this area, whether shade or broadleaf, the term "shed" is the proper term to use. Design Though tobacco barn designs varied greatly there were elements that were found in many US tobacco barns. Design elements which were common include: gabled roofs, frame construction, and some system of ventilation. The venting can appear in different incarnations but commonly hinges would be attached to some of the cladding boards, so that they could be opened. Often the venting system would be more elaborate, including a roof ventilation system. In addition, tobacco barns do cross over into other barn styles of their day. Some common types of barn designs integrated into tobacco barns include, English barns and bank barns. Each farmer has his favorite venting systems that are built not only for the winds but for efficiency. Right after the tobacco is hung, the vents are opened during the day in an effort to begin the important process of shedding water from the tobacco known as the curing of tobacco. Tobacco is often cured at specific temperatures and humidities, depending on where the tobacco is being cured, and also what the finished tobacco leaf is supposed to taste like. Cigar companies each have