Ptolemy of Alexandria, writing in the 2nd century from a city half a continent away, knew this river by name. He called it Devona, the goddess. The water that rose from a peat flat beneath Druim na Feithe in the Grampians was sacred to someone, long enough ago that a Greek cartographer would record the name without needing to explain it. Eighteen centuries later that same river still spills into the North Sea just north of Old Aberdeen, having passed castles, Roman camps, and the suburban kitchens of a modern city on its way down from the hills.
On the slopes of Brown Cow Hill, water makes a decision. Rain that falls on the northern face will join the Don and follow it east through Aberdeenshire to the cold North Sea. Rain on the western face will tip into the River Spey, slip down through Speyside whisky country, and reach the Moray Firth. Rain on the southern face joins the Dee and pours past Balmoral. Three rivers, three destinations, a few yards of summit deciding everything. The Don gathers itself from streams whose names still belong to Gaelic - the Dhiver, the Feith Bhait, the Meoir Veannaich, the Cock Burn, the Allt nan Aighean - braiding together into the embryonic river that will run for nearly a hundred miles before it tastes salt.
The Don's valley is a corridor of memory. Above Cock Bridge stands Corgarff Castle, a white-harled tower that has watched the upper Strath since the sixteenth century. Downstream, near Kintore, the river slips past the Deers Den Roman Camp - earthworks left by legions marching north under Septimius Severus or one of his successors, looking for the edge of the empire and finding instead this wide quiet straith. The river that the Romans recorded as Devona was already an old goddess by the time their boots crossed it. The current passes ice-age moraines deposited when the Grampians last lay under sheets of moving ice, then through the Howe of Alford, a basin scooped out by that same vanished glaciation.
In January 2016, after the Great Britain and Ireland floods, the Don rose to levels nobody alive had seen. At Haughton near Inverurie, the water reached 5.6 metres - half a metre higher than the November 2002 flood that had set the previous record. At Parkhill the river climbed to 5.5 metres, more than a metre above its 2002 peak. Residents were carried from their homes; care homes in Donside, the riverside neighbourhood of Aberdeen, were evacuated as a precaution. Port Elphinstone and Kintore were inundated. The river that flows quietly past sandstone villages also remembers, sometimes, that it is older than the towns it borders, and that goddesses do not always wait for permission.
For all its temper, the Don is now mostly known for what swims in it. Salmon and sea trout run up from the estuary each year, drawing fishers to Strathdon and the middle reaches. The river is one of the celebrated rods of north-east Scotland - smaller and shallower than the Spey, slower than the Dee, but generous to those who learn its pools. At Tillydrone, on the edge of Old Aberdeen, a 100-kilowatt hydro scheme spins on the site of the former Donside Paper Mill, an industry that closed and a fragment of its hydraulic logic that survived. In 1750 the river's last mile was channelled northward, shifting where Devona meets the sea, but the meeting itself has been happening for longer than any record can reach.
The River Don rises near 57.20 degrees north, 3.27 degrees west in the Grampians and reaches the North Sea at 57.18 degrees north, 2.08 degrees west, just north of Old Aberdeen. From altitude the Don shows as a meandering silver thread along the floor of Strathdon, joined by the Ury at Inverurie. Aberdeen (Dyce) Airport, ICAO EGPD, sits beside the lower river. Best viewed at 2000-4000 feet AGL on clear days; the Don is often the navigational hand-rail used by light traffic transiting between Inverness and Aberdeen.