The MHS Annex is a rustic addition to the small complex of buildings at the Allis-Bushnell House Museum. In this space are intriguing displays that reflect Madison’s past. In particular, the Annex features an exhibit on Madison's history as a shipbuilding center in the eighteenth and nineteenth centuries. The display features a narrative that describes the local  industry that flourished at East Wharf and West Wharf and includes shipwright’s tools, maritime implements, ships' models, nautical equipment, and much more.

Visitors will also see tools and implements of Madison farms and fisheries and other industries. Ingenious and timesaving domestic gadgets as well as occupational technology offer a glimpse into the nature of labor and industry both within and outside of the home. Carpentry tools, postal equipment, and weaving looms are among the objects here.

The Annex is open when the Allis-Bushnell House is open for free public tours, typically on the first and third Saturdays of each month, from 11 am to 1 pm. It can also be opened by appointment.