The lake is 2.5 miles (4.0 km) long and 0.15–0.5 miles (0.24–0.80 km) wide, lying in a channel formed by meltwater from the Puget lobe of the Vashon glacier during the Pleistocene glaciation.

[3] As indicated by a drowned forest in the lake and other evidence, the Puyallup River was inundated about 550 years ago by a lahar from Mount Rainier called the Electron Mudflow.

[4] The mudflow partially filled the channel (leading to its shallow, smooth bottom today) and blocked Ohop Creek's outlet, forming present-day Lake Kapowsin.

[1]: A69–A70 The Tacoma Rail shortline runs along the west side of the lake, as does Orville Road connecting Eatonville to the south with the town of Kapowsin.

This Pierce County, Washington state location article is a stub.