The Gilbert-Sinton Historic District is an area in the southern portion of the Walnut Hills neighborhood of Cincinnati, Ohio, United States. A triangle measuring slightly more than 13 acres (5.3 ha) in area, the district's edges are generally Morris Street and Sinton Avenue (both small residential streets) and the substantially larger Gilbert Avenue, which is concurrently designated as U.S. Route 22 and State Route 3. Most of the district was created by a small group of real estate developers working in conjunction with each other. As a result, none of the present buildings were constructed before 1880, and little construction occurred after the turn of the 20th century. Additionally, the architecture is relatively homogenous: most of...