Nissum Fjord is an inlet located in West Jutland, west of Vemb and is demarcated from the North Sea by a 13 km wide isthmus, Bøvling Klit, and passes through a lock in Thorsminde. The inlet has a water area of 70 km² or 7.000 ha. but the average water depth is only about 1 meter, and the deepest areas in Felsted Kog and the center of the inlet are between 2 to 3 meters. The northern part of the inlet, called Bøvling Fjord, is so shallow that it is sometimes completely drained by strong winds. Nissum Fjord has several creeks which empty into it, such as Ramme Creek, Flynder Creek, Damhus Creek and the largest creek, Storåen, which has its mouth at the eastern corner of Felsted Kog in the southeastern end of the inlet. Since the 1870s, Thorsminde has regulated the inlet's water level and salinity content at the lock, which facilitates water exchange in the inlet.