The house that Captain John T. Plummer first constructed circa 1842 was all but indistinguishable from the two houses north of his on Pleasant Street: all three were one story, side gable, five bay braced frame structures almost identical in terms of massing and plan. All three were essentially vernacular structures that featured Greek Revival style decorative central doors framed by almost identical sets of sidelights and top lights and ornamented with narrow pilasters and capitals. However, the Plummer House, at the south end of the street, did not retain this facade for long - some time prior to Plummer's death in 1880 the former ship captain, merchant trader, and state senator added a Gothic Revival style entry vestibule to the domicile. Measuring one and one-half stories in height, this rectangular vestibule features a pointed arch hardwood door above which is a steeply pitched gable roof. The rake trim of this roof is decorated with scroll saw cut bargeboards, and inset with flush board siding. Under the roof peak is a pointed arch tracery window. This addition represents and important, if modest, local adoption of Gothic Revival stylistic forms at mid-century. As such, the Capt. John T. Plummer House was listed in the National Register of Historic Places at the local level of significance as an example of a type, style, or method of construction that represents a stylistic trend in American architectural history.