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Urban and peri-urban lakes experience a wider array of environmental stressors, and often at a higher intensity, than their rural counterparts, including road salt runoff. A paleolimnological approach was used to determine pre-disturbance limnological conditions and to evaluate the impact of environmental stressors (nutrient inputs, climate change, and winter de-icing salt) on the long-term (~ 150 years) water quality of a small urban kettle lake in the Oak Ridges Moraine near Toronto, Ontario, Canada. Specifically, we examined Cladocera and diatom subfossils in 210 Pb-dated sediment cores from a lake with elevated measured chloride concentrations, Haynes Lake (Cl−= 201 mg/l), and a nearby reference lake located in a conservation area (Swan Lake, Cl−= 28 mg/l). In Haynes Lake, Cladocera compositional change is consistent with increasing Cl− concentrations, showing a shift from a Bosmina spp.-dominated …