Pen y Boncyn Trefeilw

About Pen y Boncyn Trefeilw

Pen y Boncyn Trefeilw is a subsidiary summit of Cyrniau Nod in the Hirnantau section of the Berwyn range, north-east Wales. It has two tops of its own, Stac Rhos and Pen y Cerrig Duon, the latter now a deleted Nuttall following re-surveying.

A small cairn marks the summit, only a few metres from a track road running on towards the pass between Cyrniau Nod and Y Groes Fagl. The outlook is broad but the flat moorland gives it little variety.

Background written from facts in the Wikipedia article on Pen y Boncyn Trefeilw (CC BY-SA 4.0). Heights, prominence and grid references come from the Database of British & Irish Hills, not from Wikipedia.

Access rights here

General position for Wales — local byelaws, seasonal restrictions and closures can override it. Full details: access rights in Wales · check another location.

Daylight at this summit today

Sunrise

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Sunset

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Daylight

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Civil twilight ends

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Computed astronomically for 52.842, -3.542. Plan your finish with the daylight safety planner.

Finding the summit

The recorded summit point is no feature: tussock. That distinction matters on broad or flat tops, where the obvious cairn is not always the true high point.

Survey method

Leica RX1250

Record revised

15-Dec-24

Drop measured from

SH973278 · 589 m

Survey notes are field observations recorded in the Database of British & Irish Hills (v18.3, CC BY 4.0) by the hill-surveying community.

Which hill this one belongs to

Pen y Boncyn Trefeilw is not counted as an independent hill in its own right. In prominence terms it belongs to Foel Cedig (668 m) — the nearest Marilyn you can reach from this summit without first dropping below its key col, 589 m.

Grouping is by prominence alone: a summit belongs to the nearest higher Marilyn it connects to without a deeper intervening col. Over a large massif that can gather hills no one would walk in a single day, and which few would describe as parts of the same mountain — it is a measure of independence, not a suggested route.

Nearest listed peaks