The house later known as the Vail House probably began as a simple farmhouse built in the 1790s by Thomas Kinney, one of Morristown’s wealthiest citizens, on a hillside overlooking the Whippany River at Speedwell, where the river’s deep ravine could be easily dammed to power an early saw mill, bloomery forge, and slitting mill. Stephen Vail, a Morristown blacksmith who began building the Speedwell Ironworks with William Campfield and Isaac Canfield in 1807 and became sole proprietor by 1815, gradually expanded his holdings from the river property acquired in the early 1800s to include the tract west of Speedwell Avenue containing the old Kinney House. By the 1840s, as a successful businessman in his 60s and owner of a large estate, he extensively renovated the house in 1844 into what he called his Mansion, choosing a traditional Georgian exterior over newer styles while adding a central heating system, indoor plumbing, a large dining room on the first floor, an office on the second floor, and a kitchen in the basement. Vail was a skilled machinist, entrepreneur, investor, and man of vision who took part in building the S.S. Savannah, financed development of the telegraph, supported railroads, served as a Justice of the Peace and a judge, was a Jacksonian Democrat and a slave owner, married three times, and died in 1864 at age 84.