Loch Insh is a freshwater loch in the Scottish Highlands, situated within the Cairngorms National Park on the River Spey in the Badenoch and Strathspey region. It lies approximately six miles south-west of Aviemore and five miles north-east of Kingussie, with the village of Kincraig just to the north. The loch is roughly rectangular in shape, measuring about 1.4 km long and 0.8 km wide, with a surface area of 1.3 km². It sits at an elevation of 214 m above Ordnance datum. Average depth is 11.4 m, with a maximum depth of 30.5 m. A small island, Tom Dubh, sits near the outlet where the River Spey continues downstream.

The loch is a well-established paddling destination, with kayaking, canoeing, and paddleboarding all available. The Loch Insh Outdoor Centre, established in 1969 and set on the eastern shore, provides equipment hire and instruction for paddlers. The centre operates its watersports activities from 1 April through the end of October. River trips are also offered, including a Kingussie to Loch Insh paddleboard route on the River Spey upstream of the loch, as well as self-led canoe and kayak river trips. The centre sits on 14 acres of woodland on the sandy banks of the loch and includes a restaurant, bar, shop, and accommodation options.

The loch is immediately downstream of the Insh Marshes, a notable wetland area, and is set against the backdrop of the Cairngorm Mountains. Fishing is a concurrent activity on the water, with populations of brown trout, rainbow trout, northern pike, European perch, and European eel present. Fishing requires a permit, and all fishing is catch and release with no bait permitted. The permit season runs from March to December. Paddlers sharing the water with anglers in boats should be aware of this activity. Sailing and windsurfing are also active on the loch, so paddlers can expect a mixed-use water environment, particularly during the summer watersports season.