The stream flows from the hills of the Aird, its source near the hamlet of Foxhole, passing the settlements of South Clunes, Easter, and Kirkhill before draining into the Beauly Firth.

According to a late-14th century transumpt of charters detailing the bishopric of Moray, Moniack (or Munythoc), was one of the nine davochs of Dunballoch, a former parish in modern-day Kirkhill.

Although its soils vary in general the gorge is highly alkaline, supporting a wide variety of vascular plants and flowers.

The name Reelig is believed to derive from the Scottish Gaelic ruighe lice, meaning "stone slope"—possibly a reference to the gorge's inland cliffs.

James Baillie Fraser, a Scottish travel writer and watercolourist, is responsible for much of the way Reelig looks today, planting many of its trees before his death in 1856.