The river rises in the town of Franklin, in Franklin County, Vermont, United States, flows west into the town of Highgate, Vermont, and then north into Saint-Armand, Quebec, in the Brome-Missisquoi Regional County Municipality, administrative region of Montérégie, in the southwest of the province of Quebec, Canada.

[1][2] The Rock River valley is crossed the following roads: The surface of the Rock River (except the rapids zones) is generally frozen from mid-December to the beginning of March, but the safe circulation on the ice is generally made from the end of December to the end of February.

The water level of the river varies with the seasons and the precipitation; the spring flood generally occurs in March.

Geographic Names Information System, it is also known as "River Rocher" and "Riviere de La Roche".

[4] In Quebec, the river appears on the 1732 map of the surveyor Jean-Baptiste Lefebvre, dit Anger, under the spelling "Rivière du Rocher".