The United States Geological Survey records the official name as Lake Oswego and, because of its artificially increased size, classifies it as a reservoir.

[5] The rocks and boulders were flung by the kolk up to a mile away to present-day Durham and Tualatin, where they were quarried for many years before the site was converted to the Bridgeport Village shopping center.

The company purchased the entire town of Oswego, including the lake and surrounding hills, which were rich in not only iron ore, but trees that would be turned into charcoal to feed the furnaces.

[13] With the relative scarcity of building easements, lakefront property remains prestigious, and a number of architecturally significant homes have been built along its shores, including the Carl C. Jantzen Estate, a Tudor-style estate on the National Register of Historic Places, built on an island on the lake's north shore by the founder of the Jantzen swimwear company in 1930.

[16] To control the waters, the corporation posted "no trespassing" signs and issued permits to select individuals who overcome various administrative hurdles.

[16][22][23][24] The corporation argued that the federal Water Resources Development Act of 1976 specifically classified the lake as non-navigable; therefore, the Attorney General opinion—which states that waterways over private land are only public if they are "navigable-for-public-use"—does not apply.

[31][32][33] The plaintiffs appealed to the Oregon Supreme Court,[34][35] which agreed to hear the case in April 2018 to determine whether the lake is public and if the city can prohibit access.

"[38] In April 2022, the Clackamas County Circuit Court found in favor of the plaintiffs, ruling that the lake was navigable at the time of Oregon's statehood and thus subject to the public trust doctrine.

[39] A second phase of the trial concluded in November 2024 and determined that the city's rules were not legal and must be changed to provide public access to the lake.

[40] Periodically, the corporation lowers the water level in the lake by opening the dam to enable lakefront property owners to conduct repairs on docks and boathouses.

[42][43] In recent years, the lake has experienced explosive algae growth, due in part to runoff from lawn fertilizer, which is rich in phosphorus.