Letronne is the lava

Lava

Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...

-flooded remnant of a 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...

. The northern part of the rim is completely missing, and opens into the Oceanus Procellarum

Oceanus Procellarum

Oceanus Procellarum is a vast lunar mare on the western edge of the near side of the Earth's Moon. Its name derives from the old superstition that its appearance during the second quarter heralded bad weather...

, forming a bay along the southwestern shore. The formation is located to the northwest of the large crater Gassendi

Gassendi (crater)

Gassendi is a large lunar crater feature located at the northern edge of Mare Humorum. The formation has been inundated by lava during the formation of the mare, so only the rim and the multiple central peaks remain above the surface. The outer rim is worn and eroded, although it retains a...

.To the west-southwest is the flooded crater Billy

Billy (crater)

Billy is a lunar crater that is located at the southern fringes of the Oceanus Procellarum, in the western hemisphere of the Moon. It lies to the southeast of the similar-sized crater Hansteen, and west-southwest of the flooded Letronne....

, and north-northwest lies the smaller Flamsteed

Flamsteed (crater)

Flamsteed is a small lunar crater located on the Oceanus Procellarum. It lies almost due east of the dark-hued Grimaldi, and north-northwest of the flooded Letronne bay on the south edge of the mare....

.

The surviving rim of Letronne is now little more than a semi-circular series of ridges. The flooded, broken rim of Winthrop

Winthrop (crater)

Winthrop is the remnant of a lunar crater that has been flooded by lava from the Oceanus Procellarum. It lies across the western rim of the much larger crater Letronne, a much larger feature that has been nearly destroyed by the intruding mare lavas...

 overlies the western wall. The rim is the most intact along the eastern stretch, forming a mountainous promontory into the mare

Lunar mare

The lunar maria are large, dark, basaltic plains on Earth's Moon, formed by ancient volcanic eruptions. They were dubbed maria, Latin for "seas", by early astronomers who mistook them for actual seas. They are less reflective than the "highlands" as a result of their iron-rich compositions, and...

. A small cluster of central rises lie at the mid-point of the crater. A wrinkle ridge traverses the floor from north to south, and outline a portion of the missing rim. The crater floor is otherwise nearly smooth and relatively free of craterlets, with the exception of Letronne B near the southeast rim.

Satellite craters

By convention these features are identified on lunar maps by placing the letter on the side of the crater mid-point that is closest to Letronne.

Letronne	Latitude	Longitude	Diameter
A	12.1° S	39.1° W	7 km
B	11.2° S	41.2° W	5 km
C	10.7° S	38.5° W	4 km
F	9.2° S	46.1° W	8 km
G	12.7° S	46.5° W	10 km
H	12.6° S	46.0° W	4 km
K	14.5° S	43.6° W	5 km
L	14.3° S	44.3° W	5 km
M	12.0° S	44.1° W	3 km
N	12.3° S	39.8° W	4 km
T	12.5° S	42.6° W	3 km

The following craters have been renamed by the IAU

International Astronomical Union

The International Astronomical Union IAU is a collection of professional astronomers, at the Ph.D. level and beyond, active in professional research and education in astronomy...

.

• Letronne D — See Scheele
  Scheele (crater)
  Scheele is a tiny, bowl-shaped lunar impact crater that lies on the Oceanus Procellarum, to the south of the small crater Wichmann. To the southwest is the flooded crater Letronne...
  
  .
• Letronne P — See Winthrop
  Winthrop (crater)
  Winthrop is the remnant of a lunar crater that has been flooded by lava from the Oceanus Procellarum. It lies across the western rim of the much larger crater Letronne, a much larger feature that has been nearly destroyed by the intruding mare lavas...
  
  .