Deuteronomy 1:2

אחד עשר יום מחרב ELEVEN DAYS JOURNEY FROM HOREB — Moses said to them: “See what you brought about! There is no route from Horeb to Kadesh-Barnea as short as the way through Mount Seir, and even that is a journey of eleven days. You, however, traversed it in three days!” — for you see that they journeyed from Horeb on the twentieth of Eyar, as it is said, (Numbers 10:11—12) “And it came to pass in the second year, in the second month, on the twentieth of the month, [the cloud went up and the children of Israel journeyed out of the desert of Sinai” (which is Horeb)] and on the twenty-ninth of Sivan they sent out the spies from Kadesh Barnea, (an interval of 40 days; cf. Taanit 29a); deduct from these the thirty days they spent at Kibroth Hataavah, where they ate the flesh “a month of days”, and seven days they spent at Hazeroth for Miriam to be shut up there as a leper, it follows that in three days they traversed all that way. — To such an extent did the Shechinah exert itself to hasten your coming to the land of Canaan, but because you became degenerate, He made you travel round about Mount Seir for forty years (Sifrei Devarim 2:2).

It is eleven days’ journey from Ḥorev by the way of mount Se῾ir to Qadesh-barnea.

אַחַ֨ד עָשָׂ֥ר יוֹם֙ מֵֽחֹרֵ֔ב דֶּ֖רֶךְ הַר־שֵׂעִ֑יר עַ֖ד קָדֵ֥שׁ בַּרְנֵֽעַ׃