What mountains can I see from here?

The mountains you can see are the ones with a clear line of sight to your eyes: not hidden by a nearer ridge, and not sunk below the horizon by the Earth's curve. A map can't tell you which those are. A panorama tool or an AR app can, by tracing the terrain between you and every summit and keeping only the peaks nothing blocks.

Why a map can't answer this

A map shows what's near you. It doesn't show what's in view. Two things decide whether a summit reaches your eye:

• Terrain in between. A 600 m hill two kilometers away can block a 4,000 m mountain fifty kilometers away. The nearer the obstruction, the more sky it covers.
• The curve of the Earth. Over long distances the ground drops away below a straight line from your eye. At 100 km, roughly 600 meters of a mountain sits below your horizon, as our guide to how far you can see a mountain works out. The atmosphere bends light slightly, which hides a bit less than pure geometry predicts.

Working out what's visible means checking every summit against both. Done for a whole horizon, that's called a viewshed, and it's why "what can I see from here" is usually answered by software rather than by eye.

How line of sight is calculated

For each candidate peak, the calculation walks along the straight line from you to the summit in small steps. At each step it compares the terrain height (lowered for curvature, adjusted for refraction) with the height of the sight line at that point. If the terrain ever rises above the line, the peak is hidden. If it never does, the peak is visible, and its height above the horizon tells you where it appears in your view.

Two practical details change the answer more than people expect:

1. Your eye height. Standing on a balcony versus the street, or a summit versus its saddle, can reveal or hide whole ranges.
2. Terrain resolution. A coarse elevation model smooths away small ridges. Good tools lean slightly toward showing a borderline peak, because a summit that just clears a ridge is still visible to you.

Tools that compute it

If you're trying to name one particular peak rather than the whole horizon, start with what mountain is this.

A worked example: Portland's volcanoes

From downtown Portland, Oregon, Mount Hood is about 78 km to the east and Mount St. Helens about 84 km to the north-northeast. Mount Adams is 120 km away to the northeast, and Mount Rainier around 165 km. All four can appear on a clear day, which surprises visitors.

Whether you see Adams and Rainier depends heavily on where in the city you stand: at that distance they sit only a degree or so above the horizon, where buildings, trees and haze get in the way first. Telling the two big cones apart is its own question; see is that Mount Hood or Mount Adams?

How Mountain Identifier: Peaks answers it

The live view does this calculation for wherever you're standing. It finds every summit within 80 km, traces the terrain to each one with curvature and refraction correction, and labels only the peaks that aren't blocked, with name, elevation and distance. Up to 26 labels show at once, spaced so they stay readable, and the three nearest visible peaks always appear.

Indoors or at night, a rendered 3D panorama draws the same view from terrain data instead of the camera, out to 120 km in the Explore tab. That's a useful way to answer "what would I see from there" before you go. The live view is part of Pro; the 3D panorama is free at 37 curated viewpoints and at peaks on your bucket list.

Frequently asked questions