Loch Long is a body of water in the council area of Argyll and Bute, Scotland.

Part of the extensive Royal Navy's, His Majesty's Naval Base Clyde.

[2][3] In Arrochar, the Royal Naval Torpedo Testing Station and Range was established on the Loch in 1912, in connection with the Clyde Torpedo Works on Eldon Street, Greenock, established in 1910.

[4][5][6][7][8] The Finnart Oil Terminal is located on the eastern shore of the loch, linked to the Grangemouth Refinery via a 58-mile-long (93-kilometre) pipeline.

[13] The steamboat Chancellor used to traverse the loch, departing Dunoon at 11:00 and returning about five hours later.