this thesis assesses the application and effectiveness of consumer-grade sonar instruments for documenting inundated archaeological sites across northwestern ontario. although the use of bathymetry and side scan sonar is commonly used by marine archaeologists, the acquisition of such data can be extremely costly, while also cumbersome in shallow water environments. many northwestern ontario lakes and rivers have complicated histories involving both human-made and natural lake-level changes that have degraded and inundated shorelines containing archaeological resources. four case studies throughout the thunder bay region were assessed using an inexpensive hull-mounted sonar system to test whether the instruments provide sufficient precision and resolution for further archaeological investigations.