The Rock River is a short tributary of Lake Champlain

Lake Champlain

Lake Champlain is a natural, freshwater lake in North America, located mainly within the borders of the United States but partially situated across the Canada—United States border in the Canadian province of Quebec.The New York portion of the Champlain Valley includes the eastern portions of...

 in northern Vermont

Vermont

Vermont is a state in the New England region of the northeastern United States of America. The state ranks 43rd in land area, , and 45th in total area. Its population according to the 2010 census, 630,337, is the second smallest in the country, larger only than Wyoming. It is the only New England...

 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and southern Quebec

Quebec

Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....

 in Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. Via Lake Champlain and the Richelieu River

Richelieu River

The Richelieu River is a river in Quebec, Canada. It flows from the north end of Lake Champlain about north, ending at the confluence with the St. Lawrence River at Sorel-Tracy, Quebec downstream and northeast of Montreal...

, it is part of the watershed

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 of the St. Lawrence River. According to the Geographic Names Information System

Geographic Names Information System

The Geographic Names Information System is a database that contains name and locative information about more than two million physical and cultural features located throughout the United States of America and its territories. It is a type of gazetteer...

, it is also known as "River Rocher" and "Riviere de La Roche."

The Rock River flows for most of its length in Franklin County, Vermont

Franklin County, Vermont

Franklin County is a county located in the U.S. state of Vermont. It is part of the Burlington-South Burlington, VT Metropolitan Statistical Area. As of 2010, the population was 47,746. Its shire town is the City of St. Albans.-Geography:...

, rising in the town of Franklin

Franklin, Vermont

Franklin is a town in Franklin County, Vermont, United States. The population was 1,268 at the 2000 census.The original name was Huntsburgh but the name was changed to Franklin in 1817.-Geography:...

 and flowing eastwardly into the town of Highgate

Highgate, Vermont

Highgate is a town in Franklin County, Vermont, United States. The population was 3,397 at the 2000 census. The town is on the border of Quebec, Canada and is a border town of Philipsburg, Quebec.-History:...

, where it turns northwardly and briefly flows for a short distance in Quebec before returning to the U.S., where it flows into Missisquoi Bay, an arm of Lake Champlain.