וַיִּ֣ירְשׁ֔וּ אֵ֖ת כָּל־גְּב֣וּל הָאֱמֹרִ֑י מֵֽאַרְנוֹן֙ וְעַד־הַיַּבֹּ֔ק וּמִן־הַמִּדְבָּ֖ר וְעַד־הַיַּרְדֵּֽן׃
Rashi on Judges
They took possession, etc., from Arnon to the Yabok. Which you claim as yours, they annexed from Sichon.
Rashi on Judges
From the wilderness to the Yardein. There was a wilderness area adjoining the Yardein.