Washington Avenue Historic District is the historic center of Cedarburg, Wisconsin, the location of the early industry and commerce that was key to the community's development. The historic district was listed on the National Register of Historic Places in 1986.
The district has 80 contributing buildings and one contributing structure in a 28acre area. Many of the buildings in this district that were built between the 1840s and the early 1900s were built out of locally mined limestone and fieldstone. Of these buildings, many are in vernacular style, but three other architectural styles are represented: Greek Revival, Italianate, and Queen Anne.
The district includes the Hilgen and Wittenberg Woolen Mills and Cedarburg Mill, which are listed separately on the NRHP.