To date, 16 Roman towers have been identified along the route of the Roman road between Greenloaning (MPK694) in the south-west to Huntingtower (MPK2223) near Perth in the north-east. In addition, two towers have also been identified on the eastern side of the River Tay near Cargill at Woodhead (MPK3672) and Black Hill, Meikleour (MPK5182].
Excavations of towers began with Christison at Witch Knowe (MPK13450) and Moss Side (MPK1933) (1901), and were followed by Robertsons’ excavations at Gask House (MPK1331), Park Neuk (MPK1394) and Roundlaw (MPK1320) in the 1960 and 1970s (Robertson 1974). Several have been excavated more recently: Westerton in 1980 (MPK786; Hanson and Friel 1996), Greenloaning (Woolliscroft and Hoffmann 1997), Shielhill South (MPK811; Woolliscroft and Hoffmann 1998), Huntingtower (Woolliscroft 2000), and Blackhill Wood, Ardoch (MPK809; Glendinning and Dunwell 2000). Excavation indicates some had their structural posts replaced, which suggests multiple phases or seasons of use although the duration of these phases and the time lapse between them remains unclear. The towers show considerable architectural variation in terms of size and construction which extends to the number of ditches surrounding them. Although proving difficult to corroborate, the towers are generally understood to be contemporary with the Flavian forts and fortlets identified along the Gask Ridge, at Cargill and Inchtuthil and considered to form a continuous visual signalling system along the road (Woolliscroft and Hoffmann 2006, 86–143, 155–7, 235–7; 2010).