Walney Channel is a narrow stretch of shallow tidal

Tide

Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....

 water in the Irish Sea

Irish Sea

The Irish Sea separates the islands of Ireland and Great Britain. It is connected to the Celtic Sea in the south by St George's Channel, and to the Atlantic Ocean in the north by the North Channel. Anglesey is the largest island within the Irish Sea, followed by the Isle of Man...

 which separates Walney Island

Walney Island

The Isle of Walney, also known as Walney Island, is an island in the United Kingdom which lies off the west coast of England, at the northern tip of Morecambe Bay. It forms part of the Borough of Barrow-in-Furness, and it is separated from the mainland at Barrow by Walney Channel, a narrow channel...

 from Barrow-in-Furness

Barrow-in-Furness

Barrow-in-Furness is an industrial town and seaport which forms about half the territory of the wider Borough of Barrow-in-Furness in the county of Cumbria, England. It lies north of Liverpool, northwest of Manchester and southwest from the county town of Carlisle...

 on the Great Britain

Great Britain

Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...

 mainland. The channel forms the head of the Furness

Furness

Furness is a peninsula in south Cumbria, England. At its widest extent, it is considered to cover the whole of North Lonsdale, that part of the Lonsdale hundred that is an exclave of the historic county of Lancashire, lying to the north of Morecambe Bay....

 peninsula

Peninsula

A peninsula is a piece of land that is bordered by water on three sides but connected to mainland. In many Germanic and Celtic languages and also in Baltic, Slavic and Hungarian, peninsulas are called "half-islands"....

 and is approximately 15 km (9 mi) in length.

At its northern boundary a permanent water channel separates North Walney

North Walney

North Walney is a National Nature Reserve on Walney Island, England. The island is an esker. The reserve has an area of 646.5 ha and protects a sand dune system which supports a large number of Natterjack Toads....

 from the Sandscale Haws

Sandscale Haws

Sandscale Haws is a National Nature Reserve on the Duddon Estuary, Cumbria, England. It is managed by the National Trust. The reserve's sand dunes support a population of Natterjack Toads, a species which is nationally rare in Britain....

 nature reserve on Great Britain. The central channel dries at low tide, where at one time numerous pedestrian causeways used to cross the channel; today, only one remains in this central section. The channel is spanned by Walney Bridge

Walney Bridge

Walney Bridge is a bridge in Cumbria, England that connects Barrow-in-Furness on the British mainland to Walney Island.-History:...

, opened in 1908, at its central point, the site of a former ferry crossing. This part of the channel was developed in the nineteenth century as Barrow's shipyard grew, the shelter that Walney Island provided the channel making it an ideal port. Dredging of the southern part of the channel was required, and still is to this day, to maintain access to the port, whilst the portion of the channel between the mainland and Barrow Island has been filled and developed to cater for shipbuilding.

The southern part of The Channel widens out into Morecambe Bay

Morecambe Bay

Morecambe Bay is a large bay in northwest England, nearly due east of the Isle of Man and just to the south of the Lake District National Park. It is the largest expanse of intertidal mudflats and sand in the United Kingdom, covering a total area of 310 km².-Natural features:The rivers Leven,...

. At its head, the southern tip of Walney faces Rampside

Rampside

Rampside is a village in Cumbria, England, located a few miles south-east of the town of Barrow-in-Furness, in the north-western corner of Morecambe Bay on the Furness peninsula.-History:...

 and Roa Island

Roa Island

Roa Island lies just over half a mile south of the village of Rampside at the southernmost point of the Furness Peninsula in Cumbria, though formerly in the area of Lancashire north of the sands. It is located at . It is one of the Islands of Furness in northern England. It has an area of about...

. Within The Channel lie Piel Island

Piel Island

Piel Island lies half a mile off the southern tip of the Furness Peninsula in the administrative county of Cumbria, though historically within Lancashire north of the sands. It is located at . It is one of the Islands of Furness in Northern England...

 and Sheep Island

Sheep Island (England)

Sheep Island is an uninhabited grassy island of around , located just over from the shore of Walney Island, opposite Snab Point. It is one of the Islands of Furness and is in the Borough of Barrow-in-Furness in Cumbria in north-west England...

, the former an historically notable site, dominated by Piel Castle

Piel Castle

Piel Castle also known as Fouldry Castle, is a castle situated on the south-eastern point of Piel Island, 1 km off the southern tip of the Furness Peninsula, protecting the deep water harbour of Barrow-in-Furness in north west England.....

. The land between Piel and Walney becomes drained at low tide, whilst a permanent channel of water continues out between Piel and Roa Island.