History of the Dene
The first reference to Holywell Dene was in 800AD although it was then known as Merkel Dene. It was part of the Manor of Hartley.
In 1219 the Manor of Hartley was conferred to Gilbert de Laval and became part of the Delaval Estate, as it is today.
About Us
In 2000 Holywell Dene was in a bad state and deteriorating rapidly. The tenant farmer’s right to over-winter cattle in the Dene had heavily affected the ground flora and natural regeneration, as well as severely damaging the numerous paths.
Welcome to Holywell Dene!
Holywell Dene is in the South East corner of Northumberland, with a small part straddling the border into North Tyneside.
The Dene stretches for approximately 6km between the villages of Seghill in the west, passing close to Holywell and Old Hartley, and thence to Seaton Sluice on the coast in the east.
Holywell Dene is a steep sided ancient semi-natural woodland and is traversed by a small river known as the Seaton Burn. Between Old Hartley and Seaton Sluice, where the river enters the sea, the valley widens into a tidal flood plain.
Much of the Dene is part of the Delaval Estate. In 2000 the Estate granted the two Councils a 99-year lease; they in turn designated their areas Local Nature Reserves.
In the same year, 2000, a voluntary community group called Friends of Holywell Dene was established.
Flora and Fauna
The woodlands of Holywell Dene, together with its adjacent agricultural fields, support a wide variety of Flora and Fauna.
Wild flowers found, which are indicators of native woodland, include:
Bluebells in the Dene
Latest News
Upcoming Events
Dates for your diaries - a list of events occurring throughout the year can be found here.
Himalayan Balsam
Himalayan balsam, an attractive but invasive alien plant, is trying to invade the banks of the river. Please keep an eye open for it, and report it if you see it. To find out what it looks like, view our Himalayan Balsam Guide.
4-Aug-2026
A dedicated team of nine volunteers met up at the Hartley Lane car park this morning, ready to take on the day's tasks despite a damp start at 19°C....
1-Sep-2026
A group of eleven volunteers met up at the Northumbrian Water pumping station this morning for a session focused on essential trail repairs and accessibility....
25-Aug-2026
A strong team of ten volunteers met up by the gate on Hartley West Farm lane this morning, ready to take on one of our major seasonal jobs....
18-Aug-2026
A small party of five volunteers met at the west end of Seaton Delaval for a morning of balsam bashing....
11-Aug-2026
A great turnout of ten volunteers met up at the car park in Mare’s Close, Seghill, this morning for another highly productive session tackling Himalayan balsam....
6-Aug-2026
A team of five volunteers met up by the Suez plant in Seghill this morning for a productive few hours of conservation work on the old nature reserve....
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