Scotland's oldest canal which once served as a defensive moat for Perth while also providing its mills with power, the Town Lade begins as a diversion of the River Almond 3 miles (5 km) northwest of the city centre. Most-likely constructed c.1150, the lade leaves the right bank of the Almond between Almondbank and the Huntingtower Hotel, above a weir called Low's Work (or Lowswark). It flows east to Tulloch, where it once supported a bleachfield, then southeast to Balhousie where it throws off the Balhousie Lade which once powered a mill to the east of Balhousie Castle. The main channel continues southeast to the edge of Perth town centre, at which point it splits into two main branches. The northern branch flows alongside present-day West Mill Street and then surges under Murray Street and Mill Street before it is again visible next to George Inn Lane, while the southern branch runs under Methven Street and Canal Street. In mediaeval times these branches formed a continuous moat running just outside the town walls, with the River Tay providing protection in the east. Within the modern town centre, the lade now largely flows underground in stone-lined culverts but is best observed where it makes a brief appearance in the vicinity of the Lower City Mills.
There were once corn and meal mills at Huntingtower, Ruthvenfield and Tulloch, together with the Upper and Lower City Mills in the town centre. The plentiful supply of water was also important for the wool, tanning and, later, dyeing industries which were all important to the economy of Perth.
The Town Lade finally falls into the River Tay, having completed a course of 4½ miles (7 km). A walkway runs alongside for much of its length.
