Where does “稚内” come from?

稚内 (Japanese) comes from Ainu ヤㇺワッカナイ, from Ainu ナイ.

Ancestry of “稚内”, step by step

Step	Language	Word	Meaning
1	Ainu	ヤㇺワッカナイ	—
2	Ainu	ナイ	—

稚内 — Etymology, Origin & Word History | Etymology Explorer