The Hallowell Historic District encompasses the commercial downtown and adjacent residential neighborhoods of Hallowell. The district contains approximately 450 buildings including commercial, residential, civic, industrial, and religious structures. Nearly 85% of the buildings in the district were constructed in the eighteenth and nineteenth centuries. Hallowell was incorporated in 1771 and at that time included land that become Augusta and Chelsea.

Designated a National Historic Landmark, the Jonathan Hamilton House is an excellent example of the Georgian style in a rural setting. The house, which overlooks the Salmon Falls River, is two-and-a-half stories and sheathed in clapboard siding with a hipped roof with dormers and four tall chimneys. The symmetrical facade has some unique features including a central door topped by a pediment and flanked by ornate pilasters and sidelights. Directly above the door is a tall rounded arch window composed of many small panes of glass.

The oldest known commercial structure in the state, the John Hancock Warehouse is located on the north bank of the York River, just east of Sewall's Bridge. The building is two stories, constructed using mortise and tenoned beams. It is sheathed in wood shingles and contains doors on three sides. The windows are located on the upper floors and contain multi-paned sashes. The second floor can be accessed via the interior staircase or a ramp on the north side.

Constructed at the turn of the nineteenth century, this one-and-a-half story cape was converted into a tea room and inn that catered to motorists along Route 1 during the rise of automobile travel at the beginning of the twentieth century. Property records pertaining to the early history of the house are unclear. Local lore maintains that the dwelling existed during the 1790s, but the first historical reference to the house is in a deed dated 1815 between two yeomen.

Located south of Durham proper, the Bagley-Bliss House is a two-story Greek Revival-style frame building with a one-and-a-half story ell. It sits on a granite block foundation and is sheathed in clapboards and wood shingles. The front elevation features a traditional central doorway with a three-panel door flanked by sidelights. Shallow pedimented lintels are present above all the windows. Local tradition notes that the house was constructed around 1770 for Revolutionary War veteran O. Israel Bagley and is considered to be the oldest dwelling in Durham.

Lebanon's Old Grist Mill is the oldest surviving industrial building in town. Built by Joseph Hardison, the large rectangular mill sits on a massive foundation of dry laid stone five feet thick tapering to a width of two feet under the sills of the building. The two-story mill is typical of eighteenth-century construction with a gabled roof, framed with heavy hand hewn timbers, and a double thickness of hardwood for flooring. Like many places in rural Maine, the mill harnessed the power of a stream for manufacturing.

St. Patrick's Catholic Church is thought to be the oldest Catholic Church in Maine and New England. The church was originally constructed without a spire, but instead had a hipped roofed belfry. The spire was added in 1866. The church sits on granite block and has walls over one-foot thick. Interestingly, limestone was brought from Ireland to make the mortar to set the brick. The entrance is a pair of simple doors below an elliptical fan. Over time stained glass windows have been added to the arched openings which were once covered by shutters.

The Louis I. Bussey School, located on US 202, was built in what was originally one of five townships granted by the Commonwealth of Massachusetts in 1794 to the trustees of Bowdoin College. A large portion of the land was sold to Dr. Elijah Dix of Boston. Notably, Dix was the grandfather of noted Maine social reformer, Dorothea Dix. The town was later named in honor of the doctor who took great interest in the development of the settlement. At the beginning of the nineteenth century the town grew rapidly.

The Arch Bridge carries Benner Road over the Pemaquid River in the village of Bristol Mills. The bridge is a single span and measures 21' long. It is constructed of rubble stone arch rings and dry laid stone spandrels. The rocks vary in size and some were roughly quarried, while others were simply used in their natural shape. The opening of the arch is 14 wide and the arch is 14 high. A metal guardrail runs along the roadway and the bridge. The date of construction for the Arch Bridge is undetermined at this time.

The Turner Cattle Pound is a well-preserved example of a once common feature in early Maine agricultural communities. Many of Maine's inland communities were agricultural settlements, embracing a more privatized model of land ownership and grazing in comparison to the publicly-held "town common" model that was more prevalent in Massachusetts. Nevertheless, in both agricultural models cattle and other livestock often wandered from their owners and communities needed dedicated places to detain these animals until their owners could retrieve them.