At 20 Pine Street North, was constructed in 1846 on the bank of the second Welland Canal by Jacob Keefer and, at that time, it contained the largest watermill in Canada. The Keefers were entrepreneurs and are considered one of Thorold's founding families. At its height, the mill was capable of manufacturing 300 barrels (89 tonnes) of flour per day and storing 70,000 bushels (1,900 tonnes) of wheat and 5,000 barrels (440 tonnes) of flour. Today, the Welland Mills building has been restored offering commercial space on the ground floor and residential apartments above.