Alberta is one of the few places on earth whose rivers drain into three different oceans. This map shows every river involved.
Every stream in the province is coloured by the basin it belongs to. There are no labels, no roads, no cities, and no borders except the province's own outline. Just the water and where it goes.
Three oceans
The colours on the map are sub-basins, about twenty of them. Each one drains, eventually, to one of three oceans.
The north and west drain to the Arctic Ocean. This is by far the largest share of the province. The Athabasca and the Peace both run north and meet at the Peace-Athabasca Delta, where they become the Slave River, then leave the continent through the Mackenzie into the Beaufort Sea. If you live north of Edmonton, your rain is most likely Arctic water.
The centre and east drain to Hudson Bay. The North Saskatchewan and the South Saskatchewan collect most of the settled corridor, Edmonton and Calgary included, and carry it east into Lake Winnipeg and out through the Nelson River.
A small wedge in the far south drains to the Gulf of Mexico. The Milk River rises in Montana, loops north into Alberta for a couple of hundred kilometres, then turns back south to join the Missouri and eventually the Mississippi. Its basin is the only part of Alberta that drains to the Gulf, and on the map it sits along the southern border with Montana.
What the divides tell you
The boundaries between the colours are drainage divides, and they are the part worth looking at closely.
The divide along the western edge is the Continental Divide, running the spine of the Rockies on the British Columbia border. That one is intuitive: mountains, obvious ridge, water falls off one side or the other.
The divides out on the prairie are not intuitive at all. They wander. They cut across country that looks flat to anyone standing on it, and the difference can come down to a few metres of elevation deciding whether a slough drains toward the Arctic or toward Hudson Bay. The map makes visible something that is essentially invisible on the ground.
How to read it
Colour has no meaning beyond separation. Each basin is given a colour distinct from its neighbours so the boundaries read clearly; the hues are not elevation, discharge, or anything else. The basins are drawn at a level of detail chosen for this province, so their size is not comparable with the basins on another province's map.
Line weight does carry meaning. Thicker lines carry more water: each river's width is set by its average discharge class in the source data. The fine capillary texture in the foothills is real: that is genuinely how densely the land is drained there.
What is not on the map is as deliberate as what is. No labels, because the shapes are the subject. No roads, because they have nothing to do with where water goes.
The data
This is rendered from HydroSHEDS, a free and public global hydrology dataset derived from elevation data. It is the same source used by hydrologists and by most serious river cartography. Nothing here is drawn by hand or traced: the network is the data, rendered directly.
Data: Contains HydroSHEDS data. Lehner, B., Verdin, K., Jarvis, A. (2008). www.hydrosheds.org
Use the map. Save it, share it, put it in a presentation or a class. It is free and it is meant to be looked at.
If you want it on a wall, the same plate is printed and framed to order: Alberta, Rivers and Basins. Every other province and territory is mapped the same way.