The largest of these on Mars is Hellas Planitia, more than 1,3000 miles wide and 3.78 miles deep
[DOC] [TLE] Hellas Planitia - Wikipedia [PAR] The basin floor is about 7,152 m (23,465 ft) deep, 3,000 m (9,800 ft) deeper than 
the Moon's South Pole-Aitken basin, and extends about 2,300 km (1,400 mi)... [DOC] [TLE] SCARS OF MARS - Thule [PAR] Mars today has an equatorial diameter of 4222 miles and a radius of 2111 miles.