In Roman times, this northernmost branch of the Rhine delta was the main distributary of this major European river.
It is an important transport connection between the ports of the Rhine delta and the industrial areas of southern Limburg and southern Belgium.
The IJssel river is the only branch of the Rhine delta that takes up tributary rivers rather than giving rise to distributaries.
The Rhine delta experiences annual flooding.
It is believed to have linked the Rhine delta with the Zuider Zee lagoon (today's IJsselmeer).
Tacitus' surviving narrative breaks off as he describes a meeting on an island in the Rhine delta between Civilis and Cerialis to discuss peace terms.
The wars were mainly about control of the Rhine delta.
More likely, the IJ is a remnant of a northern arm of the Rhine delta.
Some think this people were the Franks who fought the Frisian for control of the Rhine delta.
By the 14th century, Dutch windmills were in use to drain areas of the Rhine delta.