Because of its depth, Loch Ness is the largest loch by volume of water, with a volume of 7.4 km³. On the other hand, Scotland's deepest loch is Loch Morar (1077 feet). The longest sea loch is Loch Fyne in Argyll (approximately 44 miles long). The longest inland loch is Loch Awe, Argyll (approximately 25 miles long).

No, Loch Ness is not the longest loch in Scotland, though it is frequently mistaken for it due to its fame. The title of the longest loch depends on whether you mean a sea loch or an inland loch. Loch Fyne, a sea loch in Argyll, is the longest in Scotland, stretching for approximately 40 miles (65 km). If you are looking for the longest inland freshwater loch, that title goes to Loch Awe, which is roughly 25 miles (41 km) long. Loch Ness comes in as the second-longest inland loch at about 23 miles (37 km). However, Loch Ness holds the more impressive title of being the most voluminous lake in the UK; because of its extreme depth (reaching 755 feet), it contains more fresh water than all the lakes in England and Wales combined. While it may not be the longest, its massive volume and the enduring legend of the Loch Ness Monster (Nessie) make it the most famous body of water in the Scottish Highlands, often overshadowing its longer and deeper neighbors like Loch Morar.