Wargentin is an unusual lunar impact crater which has been filled to its rim by a basaltic lava flow, forming a raised plateau.

When the lava flow occurred, it erupted from within the crater walls and proceeded to accumulate until overrunning the lowest portion of the rim.

It is connected along the southeast rim to the slightly smaller crater Nasmyth, which is in turn overlaid by the larger Phocylides.

The crater is named after eighteenth century Swedish astronomer Peter Wargentin, who observed the brightest maximum ever recorded of the famous variable star Mira.

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to Wargentin.