Red Lake is a castle in the Reach, the region controlled by House Tyrell of Highgarden. The castle is located north-west of Highgarden and due west of Goldengrove, near the border with the Westerlands.
In the books
In the A Song of Ice and Fire novels, Red Lake is the seat of House Crane. It is located along the shores of a large lake of the same name. According to legend, in the Dawn Age the lake was originally called Blue Lake until one of Garth Greenhand's sons, Brandon of the Bloody Blade fought a battle there to expel the giants from the Reach, after this battle the lake became known as Red Lake.
Old Oak · Red Lake · Goldengrove · Bitterbridge · Tumbleton · Grassy Vale · Cider Hall · Ashford · Horn Hill · Brightwater Keep · Bandallon · Honeyholt · Oldtown (The Citadel · The Hightower · Starry Sept) · Uplands · Blackcrown · Three Towers · Sun House · The Arbor