The orcs live in the mountain range adjacent to the dwarves. They live beside ogres, giants and goblins in those mountains, although never peacefully. There are constantly wars between them over territory and the lines are redrawn and alliances changed almost daily. Travelers avoid the mountains entirely because to enter is almost certain death. This leaves the area north of the mountain range unexplored and there are no accurate maps. The orcs emerge from the mountains once in a while and attack the barbarian tribes that live south of there. This is where most half-orcs come from. The orcs take captives with them back into their mountain homes and no one knows what happens to them. It is probably better not to know given what they do to the people they leave behind.