The Blair Historic District is a historic district located in downtown Belleville, Illinois. The district encompasses a mainly commercial area on the west side of the downtown area; it includes 78 buildings, 57 of which are contributing buildings. The entire district is located within the original plat of the city, which was established following a land donation from George Blair in 1813. The oldest buildings in the district date to circa 1850; development continued from then on into the early twentieth century. Most buildings in the district are two-part brick commercial blocks designed in popular contemporary styles such as the Italianate, Second Empire, Classical Revival, and Romanesque Revival. The Reichert Business Block, a three-story structure at 200 West Main Street, has a particul