The Eos Chaos area is a part of the Valles Marineris, a set of canyons stretching across more than 4,000kms with a depth of upto 7kms. With those dimensions, it’s one of the largest canyons in the known solar system.
The Eos Chaos is only a 490kms stretch, but that’s still nearly long enough to cover the United States from the east to west coast.