Conneaut is a word of disputed meaning, believed to come from the language of the Seneca tribe of Native Americans. According to local tradition, it may mean either "place of many fish" or "snow water" (referring to Conneaut Lake, notable for its ice in winter). According to the Bureau of American Ethnology, conneaut is most likely a corruption of ga-nen-yot, meaning "standing stone." Still others believe it to be a corruption of gunniate, meaning "it is a long time since they are gone." Maps from the end of the eighteenth century spell the word Conyeayout and Connewaut.

Conneaut was originally used to name the features of a glacial valley which runs from Lake Erie at Conneaut, Ohio to French Creek near Cochranton, Pennsylvania. This valley has a split drainage: The northern part drains north into Lake Erie, and the southern part south into French Creek.

Several towns in this valley share its name:

  • Conneaut, Ohio
  • Conneaut Lake, Pennsylvania
  • Conneaut Lakeshore, Pennsylvania
  • Conneautville, Pennsylvania
  • Conneaut Township, Crawford County, Pennsylvania
  • Conneaut Township, Erie County, Pennsylvania

Four bodies of water also share the name:

  • Conneaut Creek, which flows through northwestern Pennsylvania and northeastern Ohio
  • Conneaut Lake, a kettle lake in Crawford County, Pennsylvania which drains through the Conneaut Marsh
  • Conneaut Marsh, a broad herbaceous wetland (also known as Geneva Marsh) extending several miles southeast from Conneaut Lake
  • Conneaut Outlet, which flows to the southeast from the Conneaut Marsh (formerly also called Conneaut Creek)