Founded in 1883 in Elkridge, Maryland, taking over the business of Davis & Watts, a Baltimore telegraph and electrical instrument maker active since at least 1875. The company name came from a brick viaduct built next to their plant to carry the B&O Railroad tracks — almost certainly the landmark Thomas Viaduct spanning the Patapsco River. Advertising that they made "everything electrical," Viaduct specialized in telephones, magneto bells, and telegraph equipment. Their paddle-style wall telephones of the 1890s used an ingenious arm mechanism designed to circumvent Bell's switchhook patents.
