The I-house is a vernacular house type, popular in the United States from the colonial period onward. The I-house was so named in the 1930s by Fred Kniffen, a specialist in folk architecture who identified and analyzed the type in his 1936 study of Louisiana house types.[1] He chose the name "I-house" because of its common occurrence in the rural farm areas of Indiana, Illinois and Iowa, all states beginning in the letter "I".[2] He did not use the term to imply that this house type originated in, or was restricted to, those three states.[1]