How far north did the territory of the two and a half tribes east of the Jordan reach?
The eastern territory of Reuben, Gad, and the half-tribe of Manasseh extended north to the Golan, on the east side of the Sea of Galilee. These two and a half tribes remained east of the Jordan, and their land reached that northern boundary while Israel occupied Canaan west of the river.
Les explains that Joshua, over a period of 26 years, brought the children of Israel to occupy all the land of Canaan west of the Jordan River, with the exception of two and a half tribes who stayed on the east side: Reuben, Gad, and the half-tribe of Manasseh. He emphasizes that their territory on the east side took them all the way up to the Golan, on the east side of the Sea of Galilee. He also connects this to the Gadarene maniac, saying that the man was a descendant of the tribe of Gad, which lived on the east side of Jordan, and therefore was not a Gentile.