Saltbox architecture is among the earliest types of architecture found in Colonial America. Essential features of a saltbox include a two-story house consisting of four rooms, a central chimney, a single-story rear lean-to addition and a sloping back roofline. This type of architecture resembled an English cottage and was common in rural England, where many New England settlers originated.
As the colonies prospered, saltbox architecture evolved. The lean-to addition became a full story, making for a four-on-four room house with a central hallway and staircase. This standard Colonial design featured a symmetrical front with a central door, two windows on either side and five windows across the second floor.
What made American Colonial architecture unique was how it varied depending on the nationalities of the settlers that populated the South and Eastern Seaboard. Each fashioned different versions of American Colonial architecture.
English Colonial architecture — most common in New England — featured a four-on-four room house with a central chimney to conserve warmth. Dutch Colonial — prevalent in New York City and along the banks of the Hudson River Valley — incorporated gambrel roofs and paired chimneys, details common in their Dutch homeland. French Colonial — found along the Mississippi River and in southern Louisiana — featured steep hipped roofs, dormers and stairs leading to a wrap-around porch.
By the 1750s, another Colonial style — Georgian — had become the predominant architectural style of the leisure class from Maine to the Carolinas. Classic Georgian architecture is marked by the same symmetry of earlier styles but with additional grace and distinction. Common features include sash windows, paired chimneys, pilasters or column-like boards flanking the front door and a side-gabled roof.
from Prospect Mortgage Knowledge Builder