The Twin Arch stone culvert was constructed in 1837 as part of the extension of the original Miami and Erie Canal, which ran from Dayton to Piqua. Its purpose was to carry stream water from the Howell Ditch under the Miami and Erie Canal into the Great Miami River. The canal segment that includes the culvert began construction in the early 1830s to complete the link between the Ohio River and Lake Erie. As one of the older artificial avenues of transportation, the canal provided access for the movement of goods throughout the region and encouraged the development of many of today’s significant communities in western Ohio. The culvert was built of limestone, with two spans of approximately 15-foot sides and about 2 feet between the spans, and arch barrels approximately 96 feet long. The arch barrels are made of roughly cut limestone laid with lime mortar in 6-inch courses. The headwalls curve out slightly at the ends and are made with 18-inch-thick limestone laid up dry. This masonry was constructed upon wood timbers, which were laid across wood piling foundations. In the early 1970s, a project to widen County Road 25-A between Troy and Piqua revealed that the original engineering alignment would disturb the arches. Miami County recognized their historic significance and agreed to redesign the roadway and bridge completely, shifting the road alignment west to minimize construction impact. The widening project was built in 1979-1980. Earlier, on July 17, 1978, the Twin Arch stone culvert was nominated and voted onto the National Register of Historic Places. The arches, on property of the State of Ohio and the Upper Valley Medical Center, were transferred to the Miami County Park District. At the same time, the Miami Valley Regional Planning Commission received approval in March 2000 for federal transportation funds to reconstruct the Twin Arch culvert. Since completion of the arches, the Miami County Park District has paved a small parking area and maintains the arches, footpaths, and pond at the Twin Arch Reserve.