The heartbeat of Port Wing came from the Big Mill. T. N. Okerstrom knew this was the perfect spot for a major lumber operation, but he lacked the working capital to build it himself. In 1893 Ebery Manufacturing put in the first steam powered sawmill on the north side of Bibon Lake. Less than two years later Moore Kepple Lumber Company of Warren, Pennsylvania, bought the mill site and erected a large band saw that had the capacity of sawing 70,000 board feet in a 10-hour workday. John Calkins was general manager. The mill was fed logs from about two dozen lumber camps scattered throughout the region. Those logs were flumed to the mill through waterways—the Flagg River, Bibon Lake, Larson and Kinney Creeks—and boomed into the harbor through Lake Superior. In a matter of ten years the forests were about gone. Millions of board feet of lumber had been shipped out on lake steamers to all parts of the Midwest and beyond.
In 1906 Moore Kepple sold out to T. N. and John Okerstrom, who continued the operation until December 1914, when the mill burned. After much debate, T. N. rebuilt the mill but with a circular saw that had a somewhat smaller capacity. The timber was gone, so in the fall of 1924 the mill closed its doors for good. The following March, the machinery was sold and moved to Butternut, Wisconsin.
