The Port Jefferson Village Historic District was listed on the National Register of Historic Places in 2005. Portions of the content on this web page were adapted from a copy of the original nomination document. 
The Port Jefferson Historic District includes a mix of residences, commercial buildings and a church on East Main Street, which extends south from the harbor, and residences on eight streets which rise up the hillside east of that street. The district is composed principally of residences which date from 1800 to 1915, with the vast majority being Greek Revival style and Italianate style dwellings built from the 1840s through the 1870s. Within the district are 96 contributing primary buildings and 34 non-contributing primary buildings. Among the 34 non-contributing principal buildings are 19 heavily-altered buildings dating from the period of significance and fifteen buildings constructed after 1917. There are 24 non-contributing accessory buildings, nearly all garages dating from after the period of significance, and 2 contributing outbuildings.
The Inc. Village of Port Jefferson is at the head of Port Jefferson Harbor, an inlet from Long Island Sound on Long Island's north shore. Port Jefferson Harbor has steep hills and ravines rising to the south and east and lowlands to the west. This geography concentrated development along East Main Street which runs south from the harbor along the edge of the lowland and on the steep hillside rising east from East Main Street and extending along the east side of the harbor.
The historic district includes the concentration of residential development which occurred during the peak years of shipbuilding, from the 1840s to the 1870s, in the area directly adjacent to the shipyards on the south and east shores of Port Jefferson Harbor. The area outside the boundaries of the district is characterized either by recent redevelopment or by residential neighborhoods having a much greater proportion of houses built after the 1870s and not directly connected to the historic context. The waterfront, which was the location of the shipyards, was redeveloped in the late-twentieth century and has lost integrity. The Bayles Shipyard, which adjoins this historic district, is the only shipyard site in this area which retains some integrity. The area west of East Main Street is a commercial district characterized by more late-twentieth-century redevelopment. East Main Street itself, south of the district boundary, is also marked by recent redevelopment and there are no intact buildings related to the historic context.
The contributing buildings within the Port Jefferson Historic District reflect many aspects of the historic context. Houses in the historic district were built for a wide range of individuals involved in the shipbuilding and maritime economy and illustrate the nature of the economy, the range of professions involved in it and the social and economic dynamics of the community. The historic commercial buildings and the church on East Main Street also recall the prosperous era of this economy and link the residential neighborhood to the waterfront.
The district contains only six contributing houses from the 1800s through the 1830s, reflecting the slow development of these early years of the shipbuilding and maritime economy. By contrast the district contains 71 contributing houses, five contributing commercial buildings and one contributing church that date from the 1840s through the 1870s, the boom era of shipbuilding and maritime trade. This large group of contributing buildings reflects the growth and prosperity of Port Jefferson during this period. From the 1880s through 1917, when this economy slowed and finally ended, there are ten contributing houses and two contributing commercial buildings.
The compact grouping of houses close to the waterfront and to the commercial buildings reflects the scale of the enterprise: rural shipyards building primarily sloops and schooners; and a maritime economy whose major component was coasting schooners and whose major cargo was cord wood. This economy built Port Jefferson and brought prosperity, but it was a measured prosperity. Although there are differences between the large homes of shipbuilders and important ship captains and the smaller homes of ship carpenters and captains of sloops and small schooners, both are within a relatively modest and conservative vernacular tradition. The modest houses of the ship carpenters are found side by side with the more ambitious houses of the shipbuilders illustrating the democratic nature of this small community which was focused on the shipbuilding and maritime enterprise on the waterfront.
East Broadway • Grant Street • High Street • Main Street East • Prospect Street • Route 25A • South Street • Thompson Street • Vineyard Place