Single pen architecture and double pen architecture are architectural styles for design of log, and sometimes stone or brick pioneer houses found in the United States. In double pen, two log pens (four walls of a log cabin) are built and those are joined by a roof over a breezeway in between.

An example is the William Boyd House

William Boyd House

The William Boyd House, also known as All Bright Hill, is a circa 1800 property in Franklin, Tennessee utilizing double pen architecture....

. A report about Williamson County, Tennessee historic resources states:

Double pen dogtrot design residences are also found in the county with the best examples displayed by the John Herbert House

John Herbert House

The John Herbert House, also known as Breezeway, is a property in Franklin, Tennessee that was listed on the National Register of Historic Places in 1988....

 (WM-152) and Beasley-Parham House

Beasley-Parham House

The Beasley-Parham House is located in the vicinity of Greenbrier, Tennessee, United States. The house is a double pen dogtrot design, consisting of two log pens, each with an exterior chimney, that were originally connected by an open breezeway...

(WM-433). Both houses were built with two log pens joined by an open breezeway or dogtrot and each pen has an exterior chimney. Both residences had the breezeways enclosed with weatherboard siding by the end of the 19th century. The original form and plan of the double pen dogtrot style is evident in both residences. In addition to these log homes there are many other residences included in the nomination which have one or more log pens enclosed or enlarged by later frame additions.