[citation needed] The river's source is on Mount Ōdaigahara in the town of Ōdai, Mie Prefecture, where it flows through the Ōsugi Valley.

The white rocks used in the Oshiraishi-mochi festival, an event held in honor of the periodic rebuilding of nearby Ise Grand Shrine, are taken from the Miya River's shores.

Some of the areas along the river's course, especially the Ōsugi Valley near the source, see a considerable amount of rain each year and thus are very prone to flooding.

The magistrate in Yamada (modern Ise) during the Tokugawa Shogunate felt that the river needed to be controlled because of its proximity to Ise Grand Shrine, Japan's holiest shrine; he thus ordered work to be done along the river to alleviate the problem.

Near the source, the river flows through the Ōsugi Valley, which is officially listed as one of the top three ravines in Japan for sight-seeing.