Llanesco is a Martian

Mars

Mars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...

 impact crater, 27 kilometers in diameter. It is located at 28.5S, 101.2°W, north of the crater Dinorwic

Dinorwic (crater)

Dinorwic is a Martian impact crater, approximately 56 kilometers in diameter. It is located on the planet Mars at 30.4°S, 101.6°W, northeast of the crater Virrat and north of the crater Tugaske. To the northeast of Dinorwic is the crater Caxias, and farther north is the crater Llanesco. It is named...

. It is named after a town in Spain

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

, and its name was approved by the International Astronomical Union

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...

 in 1991. According to a surface age map of Mars based on US Geological Survey data, the area around Llanesco is from the Noachian or Hesperian epoch, which places the area's age at 3.8 to 1.8 billion years. The crater's rim averages about 7,750 meters above zero altitude, and its floor averages about 7,000 meters above zero altitude. The crater is therefore approximately only 750 meters deep.