The second grist mill to be built in Arnprior, this stone building was built by Daniel McLachlin around 1850 and it remained in the McLachlin Bros.' posession until 1935. Multiple millers operated the mill and in 1898 the company began to use it as a training headquarters for boy scouts as well as a boarding house. After 1935 it was used for multiple purposes, most notably as Baird's restaurant and coin wash, owned by Bill Baird. In 1975, it was sold to the Ontario Hydro company and unfortunately gutted by fire. Today, one of the original turbines stands as a reminder of its presence, along with a plaque.
Caption reads "Another View of No. 3 Mill Looking down the lumber conveyor from sorting table. The seven cabins house the electric motors that drive the conveyor. Each drives twenty nine rolss. Lumber moving at the rate of three and a half feet a second takes nearly five minutes to reach the sorting table."
Caption reads "General View of No. 4 Showing the lumber conveyor and a glimpse of the end of No. 4 sorting table. The motor houses in this case are hung under the trestle. the tracks in the foreground leads to the gravel pit where ballast is obtained for the thirty miles of track in the lumber yard."
Caption reads "All the edgings, the slabs too small to be re-sawn, and the waste from the re-saw fall on a transfer and pass under the five slash-saws shown here. These saws, electronically driven, cut this material into four-foot lengths and deliver it to the main conveyor running full length of the lath mill."