Watersheds: St. Mary's
The St. Marys River
watershed is one of eight subwatersheds
within the Maumee River Watershed
and comprises 13% of that watershed. It
is delineated by the United States
Geological Survey as 8-digit hydrologic
unit number 04100004. The 524, 800-
acre (820 square mile) watershed is
located in Allan, Adams and Wells
counties in northeastern Indiana, and
Van Wert, Mercer, Shelby and Auglaize
counties in northwestern Ohio. (Figure E-1). The watershed contains
approximately 434 miles of tributary perennial streams. The St. Marys River originates near Minster, Ohio flowing to the northwest through St. Marys in Auglaize County, then through, Mercer and Van Wert counties in Ohio. The St. Marys River flows into Indiana southwest of Pleasant Mills, near the Indiana State Line and Highway 33. The
river continues to the northwest, flowing through Decatur, Indiana into Allen County. It joins the St. Joseph River in Fort Wayne to form the Maumee River, which flows northeast and empties into Lake Erie.
- Watershed Area - 848 square miles
- Empties To - Maumee River in Fort Wayne, Indiana.
- Land Use - 84% cropland, 7% woodland, 7% impervious
- Largest Cities - Fort Wayne & Decatur, Indiana. Celina & St. Mary's Ohio.
- Watershed Population - 768,810
- Watershed Counties - Ohio - Shelby, Auglaize, Mercer, Allen, and Van Wert. Indiana - Adams, Allen, and Wells.
Several local organizations play a role in watershed stewardship in the St. Mary's watershed. Among them is the Maumee River Basin Partnership of Local Governments.
Studies & Reports