The loch has an irregular shape, runs nearly northeast to southwest and is approximately 7 mi (11 km) in length.

The River Pattack flows into the head of the loch just below the road bridge at Kinloch Laggan.

Loch Laggan (mostly its castle) is featured in the Temeraire series of novels, being used as a base to raise dragons, because of geothermal heat sources.

[5] During summer 2019, filming for No Time to Die was taking place in and near the Cairngorms National Park.

[7] The Loch lends its name to The Laggan, a Scottish folk band, active in the 1960s and 70s who released a series of records and performed internationally.