Blanchinus is a lunar impact crater in the rugged south-central highlands of the Moon.

[1] Adjacent to its south is the crater Werner, and La Caille is attached to the northwest rim.

Blanchinus' outer rim has been significantly degraded by subsequent impacts, leaving an irregular, notched exterior ring of rugged hills and ridges.

For a few hours before the first quarter, the crater's rim contributes the lunar x visual phenomenon.

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