Loon Lake is located in western Westminster within the city-owned Loon Lake Open Space. Situated southwest of the intersection of West 100th Avenue and Independence Street, the 10-acre lake is also found northeast of Standley Lake and southeast of Wayne Carle Middle School.
Properties to the north, east and southeast of Loon Lake are developed with residences and there is no access from these areas. The area to the northwest holds the school, and to the south and southwest is Standley Lake Regional Park, particularly its massive dam and drainageway. Loon Lake is hidden from view except from the west and south.
Public access to the lake is gained from two places - the Big Dry Creek Trail below the Standley Lake dam and the middle school’s east parking lot. An informal trail from the school’s parking lot takes visitors along the northwest side of the lake and the Big Dry Creek Trail provides limited access from the south.
Loon Lake and its surrounding open space were acquired by the City of Westminster through purchases completed between 2000 and 2010.
Also known as Borrow Pit Lake, Loon Lake dates back to the early 20th century and first appeared sometime after Standley Lake was completed in 1911. While the land where the lake sits might have been excavated in association with the Standley Lake project, the amount of soil removed from this location would have contributed just a tiny fraction of what was needed for the massive dam. It appears more likely to have been developed during the 1920s in association with the Mandalay Ditch which ran through this location.
The ditch was a project of John (Frank) and Katherine Church, members of one of the most notable pioneer ranching and farming families in the history of Westminster and northeastern Jefferson County. Katherine took over management of the family ranch and related enterprises in 1925 when her husband left to develop mining interests in southwestern Colorado. She became president of the Mandalay Irrigation Company and in this capacity worked to develop the Mandalay Ditch. In 1929, Katherine developed plans for a country subdivision near Lower Church Lake known as Mandalay Gardens.
The Mandalay Ditch originated from a headgate at the Church Ditch (developed years earlier by John’s father, George Church) about one mile west of Loon Lake. From there, the Mandalay Ditch ran toward the southeast and then curved toward the northeast just above and parallel to the north shore of Loon Lake. It then crossed today’s West 100th Avenue and ran north into Ketner Lake. A lateral branching from the Mandalay Ditch brought water into the south end of Loon Lake. There does not appear to have been any obvious outflow from Loon Lake although from Ketner Lake the outflow headed to the east.
Today Loon Lake is still fed from the Church and Mandalay ditches. However, the Mandalay Ditch now disappears into an approximately 500-yard-long pipe that runs under the Standley Lake drainageway as it approaches Loon Lake from the west.
Loon Lake also appears to have been associated at some time with a farmstead located along its north shore. The farmhouse there was present by the 1930s and still exists within the walled property north of the lake (currently used to store boats and recreational vehicles). Evidently used as a farm pond, Loon Lake would have stored water for the irrigation of crop fields.
Today the lake is used solely for recreational purposes and as a wildlife habitat. Its name derives from the Loon, an aquatic bird with a haunting call that is commonly associated with the north woods of Minnesota and Canada. Five species are found in Colorado and are known to frequent some of Westminster’s lakes.