St. Catherine's Hill is a chalk downland hill and 43-hectare (110-acre) biological Site of Special Scientific Interest on the outskirts of Winchester in Hampshire, England. It is owned by Winchester College but open to the public. It is managed by Hampshire and Isle of Wight Wildlife Trust, and topped by an Iron Age hillfort, a scheduled monument. In the Black Death, plague pits were dug in the dry valley on the south side of the hill. In the Early modern period, a mizmaze was cut on the hilltop. Winchester College football used to be played on the hill; in an old custom, members of the college assemble on the hill every year, early in the morning.

The Didcot, Newbury and Southampton Railway (DN&SR) was a cross-country railway running north–south between Didcot, Newbury and Winchester. Its promoters intended an independent route to Southampton and envisaged heavy traffic from the Midlands and North of England to the port, but they ran out of funds to complete the line to Southampton. The intended heavy through traffic never materialised, and the line was dependent on larger railways—the Great Western Railway and the London and South Western Railway—for support, which was not freely given. The line opened in two stages, in 1882 and 1885.