The Dominion Building is a two-and-a-half storey Romanesque Revival institutional building constructed of brick and sandstone located at the corner of Maple Avenue and Main Street in the downtown of Sussex.

The Dominion Building is designated a Local Historic Place for its Romanesque Revival style of architecture and for its continuous use as an institutional building.

The Dominion Building is a fine example of the type of substantial architecture that was once erected by the Federal Government to establish its presence in towns across Canada. Designed by renowned Saint John architect David E. Dunham, this building has several of the identifying features of the Romanesque Revival architecture, including round arches over windows and entryways, thick, cavernous entryways and window openings, thick masonry walls and a variable stone and brick façade.

The Dominion Building is also recognized for its continuous use as an institutional building. Built in 1883, the Dominion Building was used as a post office and customs building until 1984 when it was acquired by the Town of Sussex who renovated it to house the town offices. It was the centre of town life for many years as it was a convenient gathering point for citizens to meet.

Source: Town of Sussex, Historic Places file #13

The character-defining elements relating to the architecture of the Dominion Building include:
- rectangular two-and-a-half storey massing;
- red brick and buff sandstone construction materials;
- thick masonry walls;
- hipped roof;
- modillions under wide eaves;
- symmetrical façade surrounding a central gabled frontispiece;
- sandstone stringcourses along the headers and sills of the first and second floor windows;
- circular sandstone arches over front entrance;
- depth, symmetry and shape of window and door openings;
- brick arches over windows;
- federal coat-of-arms over main entrance;
- clock at apex of gable over front entrance;
- twin gabled dormers with sunburst designs in the pediments.