Emergency services tried in vain to rescue a man from the water at Tansor, near Oundle, yesterday (Thursday).
Police, fire, ambulance and HM Coastguard were involved in the rescue attempt.
A spokesman for Northants Police said they were called to a location near the Bluebell Lakes in Fotheringhay Road, Tansor, at about 4.10pm.
But added: “Sadly, the body of a man was found in the water.
“The death is not being treated as suspicious and a report is being prepared for the coroner.”