The Caspian Sea is the largest inland body of water on Earth - and a striking north-south contrast: a shallow northern shelf you could wade far into, sitting beside a southern basin plunging past 1,000 m. Toggle the depth bands to see the three basins side by side.
Published figures: surface area about 371,000 sq km (larger than Japan); surface level about 28 m below world ocean level; north basin averages only about 5-6 m deep; south basin reaches about 1,025 m at its deepest point.
Caspian Sea 3D Explorer
This browser explorer shows the Caspian Sea as three connected basins in cross-section: a shallow northern shelf, a mid-depth middle basin, and a southern basin that plunges past 1,000 m - the depth contrast that makes this landlocked giant behave more like an ocean than a lake.
At about 371,000 sq km the Caspian is the largest inland body of water on Earth, bordered by Russia, Kazakhstan, Turkmenistan, Iran, and Azerbaijan. It has no outlet to any ocean, so its surface sits about 28 m below world ocean level and is fed mainly by the Volga River. Despite the name, low salinity in the north (closer to fresh water) versus the saltier south is one more way the "sea" is really an enormous endorheic lake.
- Toggle the depth bands to see the shallow north, middle, and deep south basins compared
- Toggle the sea-level plane to compare the surface with 0 m world ocean level
- Switch the View button to Shoreline for real measured elevation and satellite imagery of Beshbarmag Mountain on the Caspian coast
- Read area, depth, and basin figures in the panel
- Drag to orbit, scroll or pinch to zoom
- Runs fully in the browser with the vendored three.js engine - no account, no upload
| Figure | Published value |
|---|---|
| Surface area | about 371,000 sq km - the largest inland body of water on Earth |
| Surface level | about 28 m below world ocean level |
| North basin | shallow shelf, average depth about 5-6 m |
| Middle basin | average depth about 190 m |
| South basin | deepest point about 1,025 m |
| Bordering countries | Russia, Kazakhstan, Turkmenistan, Iran, Azerbaijan |
| Water balance | endorheic - no ocean outlet; mainly fed by the Volga River |
For another landlocked basin defined by a dramatic depth contrast, open the Dead Sea 3D Explorer, or compare the vertical rock layers of the Grand Canyon 3D Explorer.
The Shoreline view loads real terrain: elevation from Mapzen/AWS Open Data terrain tiles (Terrarium, derived from NASA/USGS DEMs) and true-color satellite imagery from Copernicus Sentinel-2, both covering Beshbarmag Mountain (Five-Finger Mountain), a limestone ridge on Azerbaijan's Caspian coast north of Baku that rises steeply right beside the water. Because this coastal ridge sits at the sea's own surface level, this real data shows the shoreline relief flanking the water, not the Caspian's own 1,025 m south-basin depth or its three-basin contrast; that story stays in the Depth-band basin view, which keeps its schematic cross-section unchanged and needs no network connection.
The three connected Caspian basins are drawn right in your browser with WebGL using the site-vendored three.js build, so orbiting the shallow north shelf and the 1,025 m south basin never uploads anything about your visit to a server. If WebGL is unavailable on your device, the explorer says so and still shows the area, depth, and border figures in the facts panel.
This is an educational approximation - the basin profile, boundaries, and vertical scale are schematic teaching cues, not survey data.
Frequently Asked Questions
Why is the Caspian Sea called a sea if it has no ocean outlet?
It is the largest inland body of water on Earth (about 371,000 sq km) and behaves like an ocean in scale and salinity, but it is technically an endorheic lake - it has no outlet, only inflow (mainly the Volga River) and evaporation.
How deep is the Caspian Sea?
Depth varies enormously by basin: the north basin averages only about 5-6 m, the middle basin about 190 m, and the south basin reaches about 1,025 m at its deepest point.
Why is the surface below world ocean level?
With no outlet, the surface settles wherever inflow and evaporation balance - about 28 m below world ocean level, similar in concept to the Dead Sea's much larger drop.
Which countries border the Caspian Sea?
Russia and Kazakhstan to the north, Turkmenistan and Iran to the south and southeast, and Azerbaijan to the west.
Is the Caspian Sea salty?
Yes, but unevenly - the north is much less salty (diluted by the Volga's freshwater inflow) while the south is saltier, though still far below ocean salinity.
Is this a scientific terrain model?
No. It is an educational explorer using published figures - the basin profile and vertical scale are schematic teaching cues, not survey data.