Susquehanna County preserves a range of museums and historic sites tied to local, transportation, educational, and African American history. The Susquehanna County Historical Society and Museum is located in a 1907 building once shared with the Susquehanna County Free Library. The Center for Anti-Slavery Studies promotes understanding of the anti-slavery movement in the county. Old Mill Village Museum includes relocated buildings meant to depict a typical 1800s town, and stone walls, a dam, and foundations from John Belknap's 1820s mill on Mylert Creek still remain. Shannon House, an 1830s house owned by the Harford Historical Society, stayed in the Shannon family for more than 100 years without modernization before restoration began in 1975. The Soldiers' Orphan School began as Franklin Academy in 1836, became Harford University in 1850, and after the state bought and renovated it in 1865, provided food, clothing, and education for children of soldiers who had died during the Civil War. The Martins Creek Viaduct, completed in 1914, is a 1,600-foot-long, 150-foot-high bridge built jointly by the Delaware, Lackawanna and Western railroads to shorten the route between Clarks Summit and Hallstead, and it was guarded by soldiers during World War I. Starrucca Viaduct, a stone arch bridge over Starrucca Creek opened in 1848, was then the most expensive railroad bridge built and was constructed of Pennsylvania bluestone as part of the Erie Railroad's effort to reach Lake Erie's shipping lanes. Historic Dennis Farm was settled in 1793 by a free African American family from New England, remained in the family into the 21st century, and includes two 19th century farmsteads and a family cemetery where Revolutionary and Civil War veterans are buried.