Billy is a lunar impact crater that is located at the southern fringes of the Oceanus Procellarum, in the western hemisphere of the Moon.

[1] It lies to the southeast of the similar-sized crater Hansteen, and west-southwest of the flooded Letronne.

The interior floor of Billy has been flooded by basaltic lava, leaving a dark surface due to the low albedo.

The portion of the rim remaining above the surface is narrow and low, with a thin inner wall.

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