The High Street Historic District encompasses a well-preserved 19th-century residential area of Camden, Maine. Extending along High Street (United States Route 1), the district has maintained its character since the 1920s, despite encroaching commercialization of nearby areas, and retains a cross-section of architecture of the 19th and early 20th centuries. It was listed on the National Register of Historic Places in 1989, and enlarged in 1999 to include the Olmsted Brothers-designed Harbor Park at Main and Atlantic.