Mount Stromlo

LocationAustralian Capital Territory, AustraliaGeologyVolcanic arc/beltLaidlaw VolcanicsLast eruptionSilurian period

Mount Stromlo (formerly Mount Strom^{[1][2] [citation needed]}) is a mountain with an elevation of 770 metres (2,530 ft) AHD that is situated in the Australian Capital Territory, Australia. The mountain is most notable as the location of the Mount Stromlo Observatory. The mountain forms part of the catchment area of the Cotter River which in turn is the primary water supply for part of ACT.

The rock on Mount Stromlo consists of ignimbrite from the Laidlaw Volcanics. This erupted in the upper Silurian period over the top of the Deakin Volcanics rhyodacite which is visible on the surface on the lower slopes in the east and southeast sides. The northern lower slopes are covered with a calcareous shale which is included in the Laidlaw Volcanics as it was deposited at the same time. This is cut off on the northwest side by the Winslade Fault, which heads north east to Cook and Kaleen. A spur fault heads off east from the Winslade Fault to under the Scrivener Dam. On the northwest and north side of these faults are middle Silurian period rhyodacite volcanic deposits from the Walker Volcanics. The northern side was uplifted compared with the southern side.^[3]

The name Stromlo is taken from the poems of Ossian.^[4]

Stoney Creek and its tributaries drain the north side of the mountain, The east side drains into the Molonglo River. The south side supplies Blugar Creek that runs into the Murrumbidgee River.

The summit of the mountain where the telescopes are located is elongated in a north–south direction, with a spur running to the southwest where the water treatment plant is situated.

The first telescope installed at Mount Stromlo was the Oddie telescope which was installed on 8 September 1911.^[5] The building housing this telescope was the first construction funded by the Commonwealth Government in Canberra. In January 1913 the first telephone was connected to the Queanbeyan telephone exchange.^[6]

Mount Stromlo was devastated by the Canberra bushfires of 2003. The fire, fuelled by the pine plantation that covered the mountain, destroyed or badly damaged much of the observatory and water treatment plant.^[7]

Road access is via the Cotter Road on the south side, and Uriarra Road on the east and north. The summit is reached by a road joining Cotter Road just outside Duffy.

Mount Stromlo is renowned for its extensive and well-equipped mountain biking facilities. Following the 2003 bushfires, significant trail reconstruction was undertaken, resulting in over 35 kilometres (22 mi) of cross-country trails, a downhill track, and various other cycling courses. The site hosted the UCI Mountain Bike & Trials World Championships, attracting over 30,000 visitors from 40 countries. Beyond mountain biking, Stromlo Forest Park also features an event pavilion, cafe, kids' play area, road cycling circuit, running track, and equestrian trails.