Cooperative Charting Program of the United States Power Squadrons   https://www.usps.org/index.php/2016-01-06-11-01-04/sss-cooperative-charting

The United States Coast Guard https://www.uscg.mil/

US Army Corps of Engineers, Detroit District Website https://www.lre.usace.army.mil/Missions/Great-Lakes-Information/Great-Lakes-Information.aspx#ICG_ETH_22302

NOAA https://www.noaa.gov/

DNR Boating Information https://www.michigan.gov/dnr/0,4570,7-350-79119_79144—,00.html

The Official Boating Handbook of the Michigan Department of Natural Resources https://www.boat-ed.com/michigan/handbook/page/1/Introduction/