The reason it is called the Kanya-gawa River is that there was the kanyain (also called kamiya-in), a paper mill under the direct control of Zushoryo (the Bureau of Drawings and Books) of the government during the early stages of the Heian period, along this river.
紙屋（かんや）川と呼ぶのは、平安時代の初期に図書寮（ずしょりょう）直轄の官営紙漉き場の紙屋（かんや）院（かんやいんとも言う）がこの川のほとりに設けられたからである。