Insar (Russian: Инса́р, Erzya: Инесаро) is a river in the Mordovian republic of Russia.

[1] The river gets most of its water from melting snow, and hence its discharge is at its highest during the spring thaw.

The river freezes over in November, and is icebound until April.

Towns by the Insar are Ruzayevka and Saransk.

This article related to a river in Russia is a stub.