Kilconquhar Loch is a freshwater loch and a Site of Special Scientific Interest (SSSI).
The loch appears to be a comparatively recent feature, the earliest reference being to "the gret loch callit of auld the Reidmyre" (Scots: red or reed peat bog) in 1599 and referred to as Keanwchar Loch by 1654 in Blaeu's Atlas Novus. Samples of the loch bed support its origin as a bog and there is archaeological evidence and a local tradition that fuel was extracted. Westward outflow to the Cocklemill Burn is said to have been blocked by sand in 1624 or 1625 but it is drained to the south-east by the largely underground Loch Run into Elie harbour and eastwards to the Inverie Burn.
It is an approximate rounded square in shape, and is unusual in that it has no visible inflow, yet is not stagnant. It has been theorised that an underground spring feeds into the loch, maintaining a degree of freshness sufficient to offset its stagnation.