| 1827 | Explorer Allan Cunningham names the Darling Downs. |
| 1840 | Leslie brothers establish Toolburra; head station at Canning Downs. |
| 1844 | Campbell brothers secure leases from Leslies to establish the Glengallan run. |
| 1852 | Glengallan transferred to C.H.Marshall, managed with Robert Campbell. |
| 1855 | Marshall takes-in partner John Deuchar; Glengallan Merino Stud established. |
| 1865 | Marshall returns to England. Deuchar contracts to buy-out partnership. |
| 1867 | Deuchar embarks on building program including Glengallan house. |
| 1870 | Deuchar bankrupt. Marshall forecloses. |
| 1873 | Marshall forms new partnership – W.B.Slade establishes showpiece sheep and cattle station. |
| 1895 | First resumptions under Queensland Agricultural Lands Purchase Act. |
| 1904 | Gillespies purchase homestead bock. Slade-Marshall partnership dissolved. |
| 1927 | Alex Gillespie dies. Glengallan forfeited to bank. Atkinson family moves into Cedar Wing. |
| 1931 | Oswald Slade purchases Glengallan; Cockram family lives in Cedar Wing. |
| 1946 | Cedar Wing dismantled and timber used in farmhouse at Tannymorel, later removed to Upper Swanfels. |
| 1956 | Oswald Slade dies; property bequeathed to Church of England for Slade School. |
| 1960s | Glengallan furniture and fittings removed. |
| 1972 | Smith family purchases Glengallan Station. |
| 1993 | Smiths sell House to GHT for one-third market value with proviso the place be held in trust for people of Queensland. |
| 2002 | Centenary of Federation Fund enables Glengallan restoration project; Heritage Centre established. |