Nipigon is an impact crater on Mars, located in the Arcadia quadrangle just North-East of the volcano Uranius Patera. The crater was named in 1991 after the Canadian town , Ontario. It is also worthy to note that the location crater on Earth. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On Mars large craters are named after deceased scientists, writers and others who have contributed to the lore of Mars. Small creaters (less than 60km) are named after small towns and villages.