A location on the eastern shore of Loch Long in Argyll and Bute, Glenmallan lies at the foot of Glen Mallan, 3 miles (5 km) north of Garelochhead. Once the site of a small community with a school, the houses here were demolished when a substantial deepwater pier was built in 1958 to transfer munitions to Royal Navy and Royal Fleet Auxiliary ships from the armaments depot DM Glen Douglas, located 2½ miles (4 km) to the north northeast. Known officially as the Northern Ammunition Jetty, the facility was refurbished in 1970 and completely replaced in 2021 at a cost of £64 million to support the sizeable new aircraft carriers HM Queen Elizabeth and HMS Prince of Wales. A private road now connects the jetty to DM Glen Douglas.
Glenmallan House, built in the 1820s for John Colquhoun of Luss but now owned by the Ministry of Defence, remains as an empty shell.
