The Double-pen slave cabin is a two-room house that is believed to be the oldest of the slave cabins on Welham Plantation. It was constructed around 1830 and had an unusual construction with "one-by-twelve" inch boards across the front and bevelled edge siding on the front wall. The framing is of mortise-and-tenon construction, and it has a central chimney shared by back-to-back fireplaces. This type of architectural styling is commonly referred to as "saddlebag".

Most enslaved people lived in sparsely furnished cabins with crude furniture and bedding made of straw, corn shucks, or moss laid on the floor and covered with a blanket or quilt. The chairs typically had seats made of animal hide, woven rush, or corn shucks. At the same time, handmade tools and cooking utensils were occasionally fashioned with items handed down by the overseer or plantation owner. Lighting devices were usually crude iron vessels designed to hold burning rush or grease.

The Double-pen slave cabin is now a part of the Rural Life Museum. It is furnished to depict the typical living conditions of enslaved people on Louisiana plantations during the 19th century.