Jericho Hill is approximately 500 miles north of Mejis, on the edge of the Clean Sea. Its western edge is known as the "Hill of Stone Faces" and is littered with massive sculptures of Mid-World's ancient gods. Many people think they are the leftovers of a religious rite and considered the place as haunted and unlucky.
The battle did not go well for the gunslingers. At the time of the gunslinger's final charge, the gunslingers are massively outnumbered, a dozen against two thousand. Roland escaped by hiding under the bodies of his comrades and pretended to be dead.
Many of Roland Deschain's friends died in the battle. Jamie De Curry was killed by a sniper, either by General Grissom or by his son. Alain Johns was killed by Roland and Cuthbert Allgood, who mistook him for the enemy when he was returning to camp. It's also the site where Cuthbert died while blowing the Horn of Arthur Eld. Roland never remembered to pick up the Horn after the battle.