Joshua 5:1-2 (KJV)
And it came to pass, when all the kings of the Amorites, which were on the side of Jordan westward, and all the kings of the Canaanites, which were by the sea, heard that the Lord had dried up the waters of Jordan from before the children of Israel, until we were passed over, that their heart melted, neither was there spirit in them any more, because of the children of Israel.

It appears from this verse that there were people thus denominated that dwelt on both sides of the Jordan. Those on the east side had already been destroyed in the war which the Israelites had with Sihon and Og; with those on the west side Joshua had not yet waged war. It is possible however that the Amorites of whom we read in this verse, were the remains of those who dwelt on the east side of the Jordan, and who had taken refuge here on the defeat of Og and Sihon.