[2] The district expanded by 11 acres (4.5 ha) in 1998 to encompass 50 contributing and 22 non-contributing properties and pushed the western and eastern boundaries out to Mount Rushmore Road and 5th Street, respectively.

[4] The buildings in the Rapid City Historic Commercial District represent a broad range of purposes and architectural styles.

Most properties historically served—and continue to serve—a commercial purpose, but some have been used for governmental, civic, agricultural, industrial, or entertainment functions.

[3] As white American settlers moved west into the Black Hills in the 1870s, entrepreneurs began looking to build settlements that would serve as hubs of commerce and transport.

Banks, grocers, lawyers, pharmacies, and many other retail and commercial ventures started up in the downtown core to meet the needs of the growing population.

The old fire hall also served as a police headquarters; today it is a restaurant, the theming of which calls back to its firehouse roots.

Most notably, the building features an oriel window topped with an onion dome inspired by architecture in Eastern Europe.

Only 625 was included in the original listing; the other two addresses were ineligible due to remodeling works that had obscured much of the front facades.

Later, it hosted various businesses, including the United National Bank and the Bible and Book Store on its ground floor.

[2] Properties below are listed in a clockwise direction, beginning at the intersection of Main and 5th Streets in the northeast corner of the district.