The headwaters of the East Holland River rise in the Oak Ridges Moraine.
Despite concerns of a lack of water, construction of several locks was started along the river between Newmarket and Holland Landing as part of a 'Holland River Canal' that would have joined Newmarket to the Trent-Severn Waterway.
There were two swing bridges built in East Gwillimbury; one on Green Lane and the other on Main Street North (Concession 2).
On Green Lane the road now runs slightly to the south and a pedestrian bridge crosses the old structure.
The upper limit of navigation on the East Holland River remains at River Drive Park, about 2 km downstream from Holland Landing not far from the Marina RiverSports Recreation at Queensville Sideroad.