Black Cart Water originates at Castle Semple Loch in Lochwinnoch, Renfrewshire, and flows northeast through Johnstone before passing Linwood and continuing under the M8 motorway at Blackstoun, where it is joined by the River Gryfe. From there, the river runs parallel with the main runway of Glasgow Airport before passing under the A8 road at Renfrew via a stone bridge, where it meets the White Cart Water to form the short River Cart. The accessible paddling stretch is approximately 5 kilometres, as listed on the UK river access register.

The river passes through a largely urban and semi-industrial corridor in Renfrewshire, with the proximity of Glasgow Airport's main runway being a notable feature of the lower section. The confluence with the River Gryfe at Blackstoun marks a significant point along the route, adding volume to the flow before the river continues toward Renfrew. The stone bridge carrying the A8 near the confluence with the White Cart Water is a recognisable landmark at the downstream end of the navigable section.

Paddlers should be aware that the river flows through a heavily developed area on the outskirts of Glasgow, which shapes the character of the experience throughout. Given its listing on the Action for Access register, there is recognised paddling access on this stretch, though prospective paddlers are advised to consult current access arrangements before planning a trip.