The temperature overnight had been minus 18° Celsius (0°F) so you can see ice crystals on the ice in the lower right-hand corner. The water here flows fairly fast so the freezing temperatures haven't been low enough for long enough to freeze all the water here.
Not a super-clear photo here of these crystals, some of which are about 2 inches long. I hope you understand why I decided to NOT walk out on the ice to get a closer shot.
Several creeks flow through East Gwillimbury, all flowing northerly into Lake Simcoe. This one - Mount Albert Creek - is on the east side of town. If you look closely, you can see a thin layer of ice on the creek.
This map shows the creeks and rivers that flow into Lake Simcoe. East Gwillimbury is located on the south side of the lake in York Region.
Here you can see why I take so many photos of Lake Simcoe - it's so close!