Danielson Main Street Historic District is a 20 acres (8.1 ha) historic district representing the commercial business district of the borough of Danielson in the town of Killingly, Connecticut.
It was listed on the National Register of Historic Places in 1992. At the time, the district included 49 contributing buildings.
The district focusses upon commerce. It consists primarily of commercial buildings, and is drawn to exclude nearby residential areas and industrial areas, even historic ones. The district runs along Main Street from Water Street to Spring Street.
Significant properties in the district include: