Shannon Pot

Shannon Pot Lag na Sionna
Location	Derrylahan townland, County Cavan
Coordinates
Primary inflows	Shannon Cave
Primary outflows	River Shannon
Catchment area	12.8 km²
Basin countries	Ireland
Max. length	16 m
Max. width	16 m
Max. depth	14.6 m

Shannon Pot or Legnashinna (from Irish: Lag na Sionna, meaning "hollow of the Shannon") is a pool in the karst landscape near Cuilcagh Mountain in County Cavan, Ireland. An aquifer-fed naturally fluctuating pool, it is the traditional source of the River Shannon.

The pool itself is about 16 m (52 ft) wide. It was first explored by divers in 1971 to a depth of 6 m. It was later explored by Martyn Farr among others to a depth of 9.5 m from where the water emerges from a 2 m wide fissure. In early 2009 the pot was dived to a depth of 14.6 m by Artur Kozłowski, who entered an unstable chamber.

Towns and villages near the Shannon Pot include Dowra, Blacklion and Glangevlin.

Folklore

According to legend, the Shannon is named after Sionnan, who was the granddaughter of Manannán mac Lir, the god of the sea. She came to this spot to eat the forbidden fruit of the Tree of Knowledge, which was planted by the Druids. As she began to eat it, the waters of the pool sprang up and overwhelmed her. She was drawn down into the pool and its water began to flow over the land, forming the River Shannon.

Hydrology

Surveys have defined a 12.8 km² (4.9 sq mi) immediate catchment area covering the slopes of Cuilcagh. This area includes Garvagh Lough, 2.2 km to the northeast of the pot. Water from Garvagh drains into Pollnaowen sink, before emerging at Shannon Pot.

The highest point in the catchment is a spring at Tiltinbane on the western end of the Cuilcagh mountain ridge; this sources an unnamed stream which itself feeds into Shannon Cave. Further sinks that source the pot include Pollboy and, through Shannon Cave, Pollahune in County Cavan and Polltullyard and Tullyrrakeeragh in Fermanagh.

Surveys suggest that Shannon Pot may once have had a much bigger catchment area. In times of high flow it has been shown to be hydrologically linked to Badger Pot and Pigeon Pot beside Florencecourt Forest Park, Fermanagh.

Photography

• Shannon Pot, entrance gate.jpg

  Entrance gate to the Shannon pot, off R206

• Shannon Pot, entrance gate sign.jpg

  Sign at entrance to the Shannon pot

• Shannon Pot, avenue.jpg

  Avenue leading up to Shannon Pot

• Shannon Pot.jpg

  Reputed source of the river Shannon; 'Shannon Pot'