Lake Macdonald is a rural/residential locality in the Noosa hinterland, immediately east of Cooroy and 14 km west of Noosa Heads.
The lake provides water storage for the Noosa region. Originally known as the Six Mile Creek dam, the lake has supplied town water since 1965.
There are several State forests north of the lake. On the lake's northern and western shorelines there are the Cooroora Scout Camp and the Noosa Botanic Gardens, both dating from the 1980s. The botanic garden is on a former tip site. Boating (non-combustion engine), canoeing and fishing are permitted on Lake Macdonald. There is a fish hatchery between the water-treatment plant and Camp Cooroora on the lake's northern shoreline.
South of Lake Macdonald on the Cooroy-Noosa Road there are the Figtree and Frogmouth Bushland Reserves.
Lake Macdonald's census population in 2006 was 1511.