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UpToWhere · Can you see it?

Can you see Lugnaquilla, Ireland from Yr Wyddfa (Snowdon), Wales?

Yes — you can

160 km line of sight toward the west (bearing -93°), computed on 30 m Copernicus terrain with Earth curvature and standard atmospheric refraction.

Guides on Snowdon's summit tell visitors that on the clearest days you can see Ireland across the Irish Sea. Between the two summits lies 160 km of open water — and a lot of curvature.

3D terrain view from Yr Wyddfa (Snowdon), Wales toward Lugnaquilla, Ireland
Straight-line distance160 km
Direction-93° west
Observer eye level1,071 m
Target elevation923 m
Curvature drop at the target1,752 m
Clearance margin+1 m

From Yr Wyddfa (Snowdon), Wales, at an eye level of 1,071 m, the sightline to Lugnaquilla, Ireland runs 160 km and clears every ridge in between. Over that distance Earth's curvature drops the target 1,752 m below a flat-earth line — but at 923 m, it still rises above the horizon. The view is geometrically real: whether you actually get it depends on haze, not terrain. The tightest squeeze is mid-path, where the sightline passes just 1 m above the terrain at km 160.

The line on the map

Satellite map with the sightline from Yr Wyddfa (Snowdon), Wales to Lugnaquilla, Ireland drawn in red
The 160 km sightline over satellite imagery, drawn as the great-circle path light would follow.

The terrain profile

-0 m1,000 m2,000 m3,000 m sea level (curved) sightlineYr Wyddfa (Snowdon)Lugnaquilla 0 km160 km50100
Elevation profile from Yr Wyddfa (Snowdon), Wales to Lugnaquilla, Ireland. Like every elevation profile, the vertical axis is stretched (≈15× here) — but the geometry is real: mid-path, Earth's surface genuinely stands 503 m above the straight line between the two points (the dashed arc is sea level). Light bends only slightly around that bulge, so whatever it covers stays hidden.
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Frequently asked questions

Can you see Lugnaquilla, Ireland from Yr Wyddfa (Snowdon), Wales?

Yes. The terrain-limited line of sight is clear across 160 km, accounting for Earth's curvature and standard atmospheric refraction. Atmospheric haze is the only thing that can hide the view.

How far is Lugnaquilla, Ireland from Yr Wyddfa (Snowdon), Wales in a straight line?

160 km great-circle distance, on a bearing of -93° (west).

How much does Earth's curvature hide over 160 km?

At the target's distance the curvature drop is about 1,752 m: anything lower than that (relative to the observer's horizon plane) is hidden behind the bulge of the Earth. Lugnaquilla, Ireland is tall enough to rise above it.

How was this calculated?

UpToWhere walks the full terrain profile between the two points on 30 m-resolution Copernicus GLO-30 elevation data, applying Earth curvature and standard atmospheric refraction (k = 0.13) — the same physics surveyors use. You can run the same point-to-point check between any two places on Earth.

More famous sightlines

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