It originates, near some wind turbines, at what modern maps call Avonhead Cottage south of
Upperton just west of
Longriggend. Older maps show it near Avonhead just west of "Avonhead Rows" and north of "Avonhead Coal Pit No 9". Some maps show a stream coming from Fannyside Lochs in
North Lanarkshire, some 3 miles (5 km) east of
Cumbernauld, but that is not the Avon's source even if some water drains in a rivulet from there. The west of Fannyside Loch is the source of the Glencryan Burn which ends up in the
River Carron via the
Red Burn and the Bonny Water. Herd's Hill, the source of the
Luggie Water which ends up in the
River Clyde via the
River Kelvin is close by. The first tributary of the Avon is the Shiellhill Burn on the south of
Greengairs very close to the source of the Cameron Burn, which itself is a tributary of the Luggie Water. The Avon picks up the Shiellhill Burn close to Upperton, north of the sewage works and west of Easter Glentore Farm. The Avon crosses Fannyside Road at the Bog Bridge near Toddle Knowe. Within about a kilometre of this point are streams whose waters make it to Linlithgow, Larbert and Kirkintilloch on their way to their destinations. The next tributary is the Garbethill Burn near Jawhills followed by the Rashiehill Burn. The next tributary, near
Slamannan, is the Culloch Burn which also starts in Longriggend but takes a more easterly course initially. The Culloch Burn flows anticlockwise round Slamannan and joins the Avon just to the north. After Avonbridge the Lin Mill Burn just after the start of the River Avon Heritage Trail. The next two tributaries are the Logie Water, near Westfield, and the Brunton Burn. After
Muiravonside Country Park, the other end of the River Avon Heritage Trail, the Bowhouse Burn confluence occurs just before the
Avon Aqueduct. This is the tallest aqueduct in Scotland. The
Avon Aqueduct—Scotland's longest
navigable aqueduct—carries the
Union Canal above the river. The Avon flows under the aqueduct and later under both
Linlithgow Bridge and the M9 motorway. The river broadens before it joins the
Firth of Forth just east of the
Grangemouth Refinery. This is not far down from where the Grange Burn and the
River Carron meet the Firth. The Avon flows through the
Avon Gorge and forms the boundary between
Falkirk and
West Lothian council areas. It is 19 miles (31 km) in length. ==Etymology==