Named after Percival Lowell - American astronomer (1855-1916).
Lowell is a crater in Aonia Terra, Thaumasia quadrangle, Mars. Nearby features include the craters Slipher to the north and Coblentz to the southwest, the small mountain Aonia Mons to the west, and Aonia Planum to the southeast. He used the observatory to discover over 500 canals on Mars. (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.