The Zagros form a belt of ridges across western and southwestern Iran. The Alborz rise beside the southern Caspian coast, with dry basins in the interior. The change between the Caspian lowlands and the terrain immediately south is useful regional context.
The Zagros and the Caspian margin
Compare the southern Caspian shore with the plateau beyond the Alborz. Follow where the mountain belt separates those landscapes.
Similar landscapes across borders
Dry folded ridges continue into Iraq and Turkey. Neither desert colour nor a single ridge identifies Iran. Look for the orientation of several ridges and their position relative to a coast or basin.