UpToWhere
UpToWhere Can you see it?

Can you see Mauna Kea, Big Island from Haleakalā summit, Maui?

Yes, you can

128 km line of sight toward the southeast (bearing 140°), computed on 30 m Copernicus terrain with Earth curvature and standard atmospheric refraction.

The answer

Yes. Mauna Kea, Big Island is visible from Haleakalā summit, Maui: a clear 128 km line of sight, and after Earth's curvature drops the target 1,122 m, its top still stands 25 m above eye level.

Two of the tallest volcanoes on Earth stare at each other across the Alenuihāhā Channel. From Haleakalā's crater rim at sunrise, Mauna Kea's observatories float above the cloud deck of another island.

3D terrain view from Haleakalā summit, Maui toward Mauna Kea, Big Island
Straight-line distance128 km
Direction140° southeast
Observer eye level3,055 m
Target elevation4,202 m
Curvature drop at the target1,122 m
Above your eye level25 m

From Haleakalā summit, Maui, at an eye level of 3,055 m, the sightline to Mauna Kea, Big Island runs 128 km and clears every ridge in between. Over that distance Earth's curvature drops the target 1,122 m below a flat-earth line, but at 4,202 m, it still rises above the horizon. The view is geometrically real: whether you actually get it depends on haze, not terrain.

The line on the map

Satellite map with the sightline from Haleakalā summit, Maui to Mauna Kea, Big Island drawn in red
The 128 km sightline over satellite imagery, drawn as the great-circle path light would follow.

The terrain profile

0 m2,500 m5,000 m7,500 m sightlineHaleakalā summitMauna Kea 0 km128 km50100
Elevation profile from Haleakalā summit, Maui to Mauna Kea, Big Island. Like every elevation profile, the vertical axis is stretched (≈5× here), but the geometry is real: mid-path, Earth's surface genuinely stands 322 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.
Check your own two points with the calculator →

Frequently asked questions

Can you see Mauna Kea, Big Island from Haleakalā summit, Maui?

Yes. The terrain-limited line of sight is clear across 128 km, accounting for Earth's curvature and standard atmospheric refraction. Atmospheric haze is the only thing that can hide the view.

How far is Mauna Kea, Big Island from Haleakalā summit, Maui in a straight line?

128 km great-circle distance, on a bearing of 140° (southeast).

How much does Earth's curvature hide over 128 km?

At the target's distance the curvature drop is about 1,122 m: anything lower than that (relative to the observer's horizon plane) is hidden behind the bulge of the Earth. Mauna Kea, Big Island 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

Wondering about a different pair?

The free calculator shows how far you can see from any point on Earth. Pro adds point-to-point checks: this exact analysis, between any two places you choose.

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