Bailly is a lunar impact crater that is located near the south-west limb of the Moon.

[1] The oblique viewing angle gives the crater a foreshortened appearance, and the location near the limb can limit visibility due to libration.

The most favorable time for viewing this feature is near the full moon when the terminator is crossing the crater wall.

Due to the size and the worn state of this crater, it is estimated to be more than 3 billion years old, and is part of the Nectarian system.

Selenographer Giovanni Battista Riccioli named Bailly B, Bartolus for fellow Ferrarese Jesuit Daniello Bartoli (1608-1685) in his Almagestum novum (1651).