Ogrens Lake

On the scoring rubric Ogrens Lake grades a D: clarity at 2.6 ft and 62 µg/L of phosphorus keep it in the lower bracket for Chisago County. Secchi readings are the weakest of the three parameters, suggesting suspended sediment or algal biomass dominates the optical signal.

At a TSI of 62, Ogrens Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. A maximum depth of 41 ft puts Ogrens Lake in the middle of Minnesota's depth distribution. At 48 acres, Ogrens Lake sits below the Minnesota median: a small water where shoreline activity has an outsized effect on water quality. Within Chisago County's 31 graded lakes, Ogrens Lake ranks 22 — below the local median, though not at the bottom.

Ogrens Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Ogrens Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. The grade is supported by multiple sampling years from Minnesota PCA volunteers and partner agencies, giving the letter a reasonably stable foundation.