Lilius is 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...

 impact 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 in the rugged southern highlands 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 to the north of the crater Zach

Zach (crater)

Zach is a lunar impact crater located in the heavily cratered southern sector of the Moon. To the north is the crater Lilius, while to the southeast is Pentland and to the south the larger Curtius. Due to foreshortening, the crater has an oblong appearance when viewed from Earth. The crater is 71...

, and south-southwest of Cuvier

Cuvier (crater)

Cuvier is a lunar crater on the southern part of the Moon's near side. It is attached to the east-southeast rim of the unusually shaped formation Heraclitus. To the northeast is the crater Clairaut....

. Just to the southeast is the slightly larger Jacobi

Jacobi (crater)

Jacobi is a lunar crater that is located in the southern highlands on the near side of the Moon. It lies southeast of the crater Lilius, with Cuvier to the north-northwest and Baco to the northeast. The crater is 68 kilometers in diameter and 3.3 kilometers in depth...

. The crater is named after the inventor of the Gregorian calendar

Gregorian calendar

The Gregorian calendar, also known as the Western calendar, or Christian calendar, is the internationally accepted civil calendar. It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582, a papal bull known by its opening words Inter...

, Aloysius Lilius

Aloysius Lilius

Aloysius Lilius , also variously referred to as Luigi Lilio, Luigi Giglio, or Aluise Baldassar Lilio, was an Italian doctor, astronomer, philosopher and chronologist, and also the "primary author" who provided the proposal that became the basis of the Gregorian Calendar reform of 1582.The crater...

.

The outer rim of Lilius has been worn down and rounded, particularly to the northwest where the inner wall protrudes farther into the interior floor. The lowest portion of the rim is to the south, adjacent to a crater attached to the southeast part of the outer wall. The interior floor is relatively flat and featureless, but there is a wide, domed central peak at the mid-point.

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 Lilius.

Lilius	Latitude	Longitude	Diameter
A	55.4° S	8.8° E	41 km
B	53.0° S	3.8° E	29 km
C	54.4° S	3.3° E	40 km
D	50.6° S	3.0° E	51 km
E	50.1° S	2.9° E	38 km
F	49.4° S	1.7° E	43 km
G	50.0° S	0.7° E	7 km
H	50.5° S	0.8° E	9 km
J	56.3° S	1.8° E	13 km
K	53.6° S	2.2° E	23 km
L	54.9° S	2.5° E	6 km
M	56.2° S	2.9° E	11 km
N	49.0° S	2.8° E	5 km
O	55.4° S	3.6° E	7 km
P	55.9° S	3.9° E	4 km
R	54.6° S	4.4° E	9 km
S	52.8° S	5.9° E	14 km
T	55.9° S	7.5° E	5 km
U	53.5° S	7.6° E	8 km
W	53.6° S	8.3° E	9 km
X	53.5° S	9.9° E	4 km