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 cultural geographer at Louisiana State University who was a specialist in folk architecture. He identified and analyzed the type in his 1936 study of Louisiana house types.[1][2][3]
He chose the name "I-house" because the style was commonly built in the rural farm areas of Indiana, Illinois and Iowa, all states beginning with the letter "I".[4] But he was not implying that this house type originated in, or was restricted to, those three states.[1] It is also referred to as Plantation Plain style.