To the residents of Trumbull County, Mosquito Lake, one of the largest lakes in Ohio, is a premier location for family camping and various water recreation activities. However, many are unaware of the geologic and glacial activities that shaped the area into what it is today. The objective of this project was to conduct a detailed investigation to better understand the geologic history of Mosquito Lake State Park.

Detailed investigation of the park was conducted through field work and published geologic data. From this data, bedrock and glacial geologic maps were derived using ArcGIS and MicroDEM mapping programs. Water well data was also used to determine the thickness of glacial material as well as subsurface bedrock formations. An east-west cross section was constructed to show the park’s geology in the subsurface.

The geology of the park shows a history of glacial advances during the Pleistocene that deposited drift material over older bedrock. Bedrock geology consists of Mississippian shales and sandstones that were deposited along ancient shorelines in delta and offshore marine environments. The area was later covered by several ice advances of the Wisconsinan Glacier during the late Pleistocene. The park contains three distinct glacial features: portion of the Defiance End Moraine, 40 to 70 feet thick, located in the southeastern sections of the park; ground moraine, 10 to 20 feet thick, forming the relatively flat surface of the western section of the park; and lacustrine deposits of former Rock Creek Lake located in the northern part of the park.