Olympus Mons: how big is the giant volcano on Mars?

Measured facts

Feature type

Shield volcano

Body

Mars

Latitude

18.65°

Longitude

-133.80°

Diameter

610 km

Approach altitude

950 km

Catalogued surface imagery

232 m/pixel source; 326 m/pixel finest delivered tiles at equator

Classification

IAU named feature · Viking imagery

Explore the caldera and the wider Martian landscape

Use Fly to Olympus Mons above to locate the volcano on Mars. Once the flight finishes, drag to change your view and scroll or pinch outward to see its position on the planet. Return to Earth is always available.

Look for the summit caldera in the source imagery, then compare the volcano’s broad footprint with the curvature of Mars. This is an orbital map investigation: the current view does not provide a walkable summit or displaced elevation geometry.

Height, diameter and why the numbers differ

ESA’s 2023 Mars Express account quotes 21.9 km at the peak. Height depends on the reference surface and is a different measurement from a feature’s catalogue diameter. The 610.13 km diameter below is an IAU naming-record value, not a terrain-height measurement made by COSMOS.

The map lets you locate and inspect the volcano’s imagery. Shading already present in a photograph or mosaic can suggest relief, but it does not turn the spherical map into a measured 3D mountain. The scientific distinction matters when comparing a broad shield volcano with a steep mountain on Earth.

What you are looking at

The feature resolves its parenting body from the record, so the flight is a Mars-centred descent rather than a lunar or generic camera move.

Approach stops at 950 km, which keeps the caldera inside the delivered Viking mosaic resolution rather than enlarging map pixels.

The IAU coordinates for this volcano are quoted as 18.65°N and 226.20°E east-positive. These are feature coordinates, not elevation data, and COSMOS never treats them as a height model.

Catalogue record

The feature record is a provenance-carrying object, not a label pasted onto a texture: IAU named feature · Viking imagery. Its name, centre and diameter are adopted from the IAU, while the visible surface remains the parent body’s observational mosaic.

Nomenclature source

USGS Gazetteer of Planetary Nomenclature

Source record

https://planetarynames.wr.usgs.gov/Feature/4453

Provenance category

measured-catalogue-data

Parent imagery category

observational-composite

Limitations COSMOS discloses

• No MOLA elevation is integrated, so the volcano’s relief is visible only through the shading baked into the Viking mosaic.
• The underlying mosaic is historical; the volcano is not imaged at the selected ephemeris date.
• Feature coordinates describe a location on the surface. They do not supply slope, height above datum or a landing site.
• A feature coordinate in this catalogue is a catalogue entry. It is not an observation of the feature at the selected date.

Sources and further reading

• ESA/Mars Express: Olympus Mons peak height and surroundings (2023)
• IAU catalogue: feature name, centre and diameter