Historic districts in the United States

In the United States, a historic district is a group of buildings, properties, or sites that have been designated by one of several entities on different levels as historically or architecturally significant. Buildings, structures, objects and sites within a historic district are normally divided into two categories, contributing and non-contributing. Districts greatly vary in size: some have hundreds of structures, while others have just a few.

The first U.S. historic district was established in Charleston, South Carolina in 1931, predating the U.S. federal government designation by more than three decades.

More information on the Wikipedia page.

The Wikipedia category page, with a list of districts is