Albert Barnes Commentary Judges 5:17

"Gilead abode beyond the Jordan: And Dan, why did he remain in ships? Asher sat still at the haven of the sea, And abode by his creeks." — Judges 5:17 (ASV)

The land of Gilead, on the east of Jordan, was divided between Gad and the half tribe of Manasseh, who are both included here. Joppa was in the territory of Dan (Joshua 19:46), and was in later times the seaport for Jerusalem.

His breaches—rather, havens; that is, the creeks, bays, and river mouths by which their coast was broken (Joshua 19:29).