| Sidown Hill | |
| Elevation M: | 266 |
| Elevation Ref: | [1] |
| Prominence M: | 34 |
| Parent Peak: | Walbury Hill |
| Location: | Highclere, Hampshire, England |
| Range: | North Hampshire Downs |
| Coordinates: | 51.3144°N -1.3614°W |
| Grid Ref Uk: | SU444573 |
| Topo: | OS Landranger |
At 255m (837feet), Sidown Hill is the third highest hill in the county of Hampshire, England.
At the summit is a mid-18th century Grade II listed building known as Heaven's Gate which is hidden by the trees covering the top of the hill.[2]
The hill is on the watershed of the Hampshire Basin and forms part of the Hampshire Downs.[3] To the east is Beacon Hill (261m (856feet)).
On 5 May 1945 a USAAF B-17 Flying Fortress of 326th Bombardment Squadron crashed on Sidown Hill with the loss of six of its crew of seven.[4]