Blackwater Lake

Blackwater Lake is located 7 miles southwest of Longville, MN in Cass County. It is a basin lake covering 761 acres (Table 1). Blackwater Lake has two inlets and one outlet, which classify it as a drainage lake. Water enters Blackwater Lake from Mule Lake in the southeast and Island Lake in the southwest. It flows out of Blackwater Lake in the north on to Woman Lake. Blackwater Lake has been monitored consistently since 1988 (Tables 2–3). These data show that the lake is on the oligotrophic/mesotrophic border (TSI = 40) with clear water conditions most of the summer and excellent recreational opportunities. The Blackwater Lake Association has been in existence for almost 20 years now and they are proud of their many accomplishments. To list a few: removal of a wandering bogs (ongoing), fish stocking and studies (in cooperation with the DNR), water level control (beavers, culvert and water control device), aquatic plant study, secchi disk readings, the acquisition of the eagles nest property to preserve it forever, free septic system testing, the BLURB (their news letter which we mail to people's home), and a web site ( They are also a member of the Association of Cass County Lakes (ACCL).
Date Issued
2012 (year uncertain)
Number of Pages
Associated Organization
Body of Water
Rights Holder
Minnesota Water Research Digital Library
Rights Management
Creative Commons