The folk culture of the middle states was less dominated by Anglos than the Yankee and Upland South regions and therefore absorbed more influences from Northern Europe. The simple Hall and Parlor house, and its larger cousin known as the I-House are the two main folk house types of these regions. From a hearth zone in Maryland and Virginia, these houses diffused westward across the Appalachians into the states of the old Midwest where they were once very dominant especially in rural areas, but it's not hard to find I-I-Houses in the Piedmont regions, where they occasionally stand side-by-side with houses regularly associated with the Upland South.
Common design features include: gable-end chimneys, modest attached porches, and highly symmetrical room configurations .
The Hall and Parlor house was a common house type in Europe and early examples date to pre-historic times. In the US, this house features gable-end chimneys and two rooms adjacent a central hallway. The front door is almost always centered between two or four windows. Rarely do 21st century examples contain only two rooms. Most feature one or more room additions.
The I-House is in many ways a two-story version of the Hall and Parlor House, with a central stairway leading to a second floor hallway, flanked by two bedrooms. The ubiquity of this house on the rural landscapes of Indiana, Iowa, and Illinois led Geographer Fred Kniffen to name these "I" houses in reference to those states. They are commonly found in the Piedmont and Shenandoah Valley as well, an indication of their evolution in the coastal Mid-Atlantic colonies, and the pathway of westward migration.