Joshua 18:18

And passed along toward the side over against Arabah northward, and went down unto Arabah:

Joshua 18:18 stands in the closing chapters of the book dealing with the conquering of the Canaanites and the division of the land among Israel. Within that portion it belongs to the account of the distribution of Canaan among the tribes. More specifically, it is part of the description of Benjamin's inheritance in Canaan, within territory adjoining Judah. That distribution rested on written documents that accurately recorded the land and its boundaries, and this verse is one of those geographical boundary details.