Parameters characterizing the long term (> 5 years) surface water quality and chemistry of 294 lakes in the Twin Cities Seven County Metro Area. These data were originally sourced from the Minnesota Pollution Control Agency and individual water monitoring groups. All data come from the top two meters of the water column, and the shallowest data were selected if there were multiple results for the same parameter (i.e. a profile was taken). In the case of multiple spatial measurements on a single lake or multiple agencies sampling the same lake on the same day, chemistry data were averaged to generate a single value per lake x date x parameter. For secchi data, the deepest reported observation on a given lake x date was retained. Parameters: total phosphorus, total nitrogen, total Kjeldahl nitrogen, nitrate, nitrite, nitrate + nitrite (NOx), ammonium, chlorophyll a (corrected and not corrected for pheophytin), specific conductivity, chloride, and secchi depth.