Long since demolished, the castle lay high on the east bank of the River Clyde, near the confluence with the Mouse Water.

[1] As a key strategic high point over the Clyde Valley, the Romans built a fortification on what is still known as Castle Hill, south west of the modern town centre.

Other fortifications were built on the site after the Romans' brief occupation of southern Scotland came to an end.

Some records claim that Kenneth II held a parliament at Lanark Castle in 978.

Lanark Castle was most likely built during the reign of David I, and was probably completed by 1144 when the town became a Royal Burgh.