Gilead was the grandson of Manasseh. The name here refers in the first place to the eastern half of that tribe. No doubt it also included the Gadites, though, since that tribe had settled between Reuben and eastern Manasseh, and came to possess part of the region named Gilead (see Joshua 13:25, Joshua 13:31).1
17 Gilead stayed beyond the Jordan; and Dan, why did he stay with the ships? Asher sat still at the coast of the sea, staying by his landings.