 A few years after starting work on the canal, Ferguson had a lake built on flat land to the front of the mansion house. The landscape gardener William S. Gilpin was carrying out work on the adjacent Strichen estate at about the same time, and it is assumed he helped with the work at Pitfour. The lake extends to almost 50 acres (20 hectares) and is 174 feet (53 metres) above sea level. Designed in the same style as the lake in Windsor Great Park, the lake was stocked with trout, both rainbow and brown; there were three bridges and four islands. The siting of the lake meant the driveway had to be moved, and ornate bridges were constructed to cross the water. Built from granite, the northern bridge has three arches with ashlar starlings, the southern bridge has a single arch and the third, smaller bridge crosses a large stream that drains into the lake.
