The following places have no minimum size for houses:
- Sarasota County, FL
- Union Mills, NC
- Newfield, NY
- Philadelphia, PA
- Spur, TX
However, be aware that there may be minimum size restrictions imposed by a Homeowners Association, if the lot is in a development.
This list will grow as we learn more of the local zoning laws.
Note that houses must still meet building codes.
Example: IRC 2012, SECTION R304 MINIMUM ROOM AREAS
R304.1 Minimum area.
Every dwelling unit shall have at least one habitable room that shall have not less than 120 square feet (11 m2) of gross floor area.
R304.2 Other rooms.
Other habitable rooms shall have a floor area of not less than 70 square feet (6.5 m2).
R304.3 Minimum dimensions.
Habitable rooms shall not be less than 7 feet (2134 mm) in any horizontal dimension.
R304.4 Height effect on room area.
Portions of a room with a sloping ceiling measuring less than 5 feet (1524 mm) or a furred ceiling measuring less than 7 feet (2134 mm) from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required habitable area for that room.
Two years later it would be great to see what an update of this list would look like given the slow, but existing growth in other areas around the country
Knoxville, TN allows tiny houses on foundations.