Charles Ellicott Commentary Deuteronomy 1:19

"And we journeyed from Horeb, and went through all that great and terrible wilderness which ye saw, by the way to the hill-country of the Amorites, as Jehovah our God commanded us; and we came to Kadesh-barnea." — Deuteronomy 1:19 (ASV)

By the way of the mountain of the Amorites. —Rather, in the direction of the mount. They did not pass the Mount of the Amorites, but went through the great and terrible wilderness from Sinai to Kadesh-barnea. So Moses says in Deuteronomy 1:20, You are come to the mount of the Amorites.