Lebesgue is a small lunar

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

 that is located near the eastern limb of the Moon

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

. It lies in the southeastern part of the Mare Smythii

Mare Smythii

Mare Smythii is a lunar mare located along the equator on the easternmost edge of the lunar near side. The Smythii basin where the mare is located is of the Pre-Nectarian epoch, while the surrounding features are of the Nectarian system...

, to the southeast of the crater Warner

Warner (crater)

Warner is a lunar crater that is located in the southern part of the Mare Smythii, near the eastern limb of the Moon. In this location the crater is viewed almost from the edge from Earth, and is sometimes hidden from sight due to libration. The crater lies just to the south-southeast of the very...

. The southeastern rim of Lebesgue is attached to a small crater that overlays the northwest rim of Swasey

Swasey (crater)

Swasey is a small lunar crater that lies along the eastern limb of the Moon. It lies near the southeastern edge of the Mare Smythii, to the west of the walled plain Hirayama...

, so that the three form a short crater chain. This is a circular, bowl-shaped crater formation. It is not notably eroded or overlain by impacts.