It encompasses 187 contributing buildings in the central business district and surrounding residential areas of Middletown.

Residential buildings include notable examples of the Late Victorian and Federal styles.

Notable non-residential buildings include the Witherspoon Inn (1761), S. M. Reynolds and Company (1871), Delaware Trust Company (1918), People's National Bank (1884), and Forest Presbyterian Church (1851).

Also located in the district is the separately listed Middletown Academy or Town Hall (1827).

This article about a property in Delaware on the National Register of Historic Places is a stub.