Four Mile Bridge (Pontrhydybont)

We’ve just returned from a week’s break on Anglesey, or to be specific Holy Island, which is the smaller island off Anglesey from where ferries depart for Dublin. We spent time at Four Mile Bridge, which really goes by the name of Pontrhydybont. This translates slightly confusingly as bridge-ford-bridge. It’s just off the A5, the road built by the Romans which runs from London all the way to Holyhead. Even in the age of motorways it’s still an important and busy route. It begins in Marble Arch which is why at the quayside in Holyhead there is a smaller version of the arch to signify the end.

Looking south-east from the bridge towards Snowdonia

It’s called Four Mile Bridge as it’s approximately four miles from Holyhead on the old stagecoach route. Before the Stanley Embankment was built by Thomas Telford and opened in 1823 this is the route travellers to Ireland would’ve taken. For centuries this short crossing was the route between the islands. Jonathan Swift – author of Gulliver’s Travels – would’ve travelled this way, but delays to sailings meant he wasn’t always happy. Read more here.

Tide waters gush through the bridge

There is a small gap in the bridge, otherwise the structure is solid, so it causes tide water to rush through. Perhaps this is why this area of inland sea is favoured by kayakers and paddleboarders. There is saltmarsh and low-lying gravelly land, fringed with tussocks of grass and gorse. It’s popular with ornithologists. Holyhead Mountain can be seen in the distance to the left and the chimney of the former Anglesey Aluminium site. This piece captures a short walk around this bit of coast.

Joe searching the saltmarshes

Beneath, as we crossed the duckboards we saw someone had marked out a path along the shore in pebbles. It’s a strange hinterland where the mud is thick and oozes but the sea so shallow it is almost a blanket.

Who marked this path?

The hot weather caused the mud to crack like scales.


Below is a view of the liminal land looking towards the A5 embankment. It’s hard to see where land and shore and sea begin. The house on the left is in a beautiful spot albeit just yards from the busy A5/A55 and Euston-Holyhead railway line.

Saltmarsh looking towards the A5

I’m glad to say there was not much litter, but craft had been abandoned to the sucking mud and rusting anchors.

Abandoned boats

This is the view towards Trearddur Bay, where Holy Island is thinnest. Indeed, in high tides the island can be cut in half here when the waters of the inland sea rise to meet the Irish Sea.


We made our way through a small wood and along the path. In the distance a lone swimmer, picked out against the shimmering waters, did backstroke. We followed a service road by the A55 and passed some magnificent properties. It was a genuine and pleasant surprise to emerge through a gate to be beside Fron Haul, Welsh for Slope or Breast (of a hill) in the Sun. In the 1970s, before I was born my great grandmother lived here. My great grandfather, a railwayman called William Hillier, worked on the London North Western (LNWR) Railway and is buried nearby at Llanfair-yn-Neubwll.

Fron Haul

It’s a short walk along the Valley (Y Fali) Road back to Four Mile Bridge.

Holy Island shore at Four Mile Bridge
Sunset over Holyhead Mountain
Moon over the water
The village
Tide water at sunset

Below is the bungalow where we stayed. Almost everything – beach, cafes, pubs, chippy, hotel and walks – were walkable. A lot of people visit Anglesey for the beaches but a walk in the interior of the island, or even the quieter inland sea is a wonderful experience. We saw swifts, egrets, heron, mullet, dogfish and quite a few Hawk jets from RAF Valley. I’ll write further on other parts of the island including Amlwch, Llangefni and Beaumaris soon.

The garden

4 thoughts on “Four Mile Bridge (Pontrhydybont)

  1. Thank you for connecting with our blog. Very much enjoyed your piece on 4MB. Also interested in your mention of William Hillier. As a Hillier, I have not come across another family spelling the name as this around Holyhead where I was born. There is a family that spells their name Hilyer. They lived in the Kingsland area and worked on the railway. Is this the family you are connected to? Regards, Barry Hillier – Trustee, Holyhead Maritime Museum.

    1. Hi Barry, thanks for stopping by. I’ve seen the name spelt differently even in my family! With a Y and ier. I know William came from Bristol originally and my great nan’s side were from Shropshire. So my nan grew up in Euston, Stafford and then Valley due to the railway. I think he died quite young but I need to some research…

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