Hartwood Acres is629-acre county park in Allegheny County, Pennsylvania in the United States. Hartwood is considered the crown jewel of the county's 12,000-acre network of nine distinct parks. Purchased by the county in 1969, its special feature is one of the largest and most spectacular country estates in the region. Hartwood consists of a stately Tudor mansion, an English style Formal Garden, a cottage, a stable complex, and a gate lodge (erected in 1927).