One Family, One Business, One Hundred Years A little about us. Soo Mill was founded in 1915 by Fremlin Hollingsworth and is currently in its 3rd generation of ownership. Soo Mill is the leading building supplier in the Algoma District with stores in Sault Ste. Marie and Elliot Lake, and a roof truss manufacturing plant in Sault Ste Marie. more... See more text