The road measures 24.09 miles long and would take a car obeying speed limits 41 minutes to travel its length.
The B840 is a B Road and is located in the Zone 8 Highways Region.
This is a true long-distance route, journeying through numerous towns like Ford, DALMALLY, Eredine, Portsonachan, Ardbrecknish, and Cladich.
The road is located entirely within Argyll and Bute.