The use of log marks was a method of establishing ownership during Michigan's White Pine lumber era (1850 - 1910), similar to cattle branding. On investigating old logs which surrfaced in Clare County lakes, the author began a state-wide research project to catalog log mark registrations and their activity as owners changed over the years. Did you know that the Boeing family fortune (later founding the aircraft company) started with Michigan timber? It is hoped that this work assists other historians in studying the logging period of the Great Lakes State's past. Log mark images and related information of log marks registered/recorded with County Clerks/ Booming Companies in the Upper Peninsula & Northwestern Lower Peninsula. On searching a log mark, one can find related activity; and the search and activity tool will allow for in 2027 of over 12,500 original soucre log mark entries photographed/scanned, to be available on a thumb drive at minimal cost upon request to museum@clarecountyhistory.org