Eaton Hall, Norman-style house in King City, Ontario, Canada.

Eaton Hall is a castle-like house in King City, Ontario, built 1938–39 for Lady Eaton from Humber Valley limestone and roofed with red Ludowici tile. It has one square turret and two round turrets, one holding a grand spiral staircase, plus a porte-cochere, ironwork and tall chimneys. It contains 72 rooms and stands beside Lake Jonda.

Lady Flora McCrea Eaton had Eaton Hall built in 1938–39 on a 700-acre parcel she and her husband Sir John Craig Eaton had assembled from 1920–22 on the advice of Sir Henry Pellatt. She moved in three years after selling her Toronto mansion, Ardwold. Architects Peter L. Allward and George Roper Gouinlock designed it; John W. Bowser of the Aurora Building Company supervised construction. From July 1944 the Royal Canadian Navy used it as a convalescent hospital, with about 100 people housed there.

The house takes its name from the Eaton family, owners of the Toronto department store chain Eaton's, and Lady Eaton's son John David gave Lake Jonda its name from the first three letters of his first and middle names. From 1929 hunters of the Toronto and North York Hunt Club met for breakfast at Eaton Hall, rode on the adjacent Pellatt Estate and returned for afternoon tea. Seneca College and the Township of King agreed in 2021 that residents, community groups and non-profits could use the building for events and programmes.

The estate now functions as a community space and offers visitors the chance to explore its rooms and grounds. Plan time to see multiple levels and outdoor areas, particularly if you are visiting as part of an organized group.

From July 1944 the Royal Canadian Navy used the house as a convalescent hospital and rehabilitation centre, housing about 100 people; by Christmas 1945 only a skeleton staff remained. Seneca College took over the estate in 1971 and used Eaton Hall as its administrative building until a new facility opened in 1977.