The majority of the data represents sites sampled in the Northern Highland Lakes District of Wisconsin. However, there is also data from Wisconsin located in Waupaca, Waukesha, and Dane counties. The Minnesota lakes featured in the database are from northern Minnesota, including lakes in Itasca, Beltrami, Anoka, Cass, Hennepin, St. Louis, Cook, and Lake counties. Data from lakes in New York was collected from only three lakes near Syracuse and Rochester, New York. Buckeye Lake, located in Licking County, is the only Ohio lake in this data set.  Data from all lakes, rivers, and creeks in Alaska was collected on Kodiac Island. Lake data from the United Kingdom was compiled from lakes and reservoirs across the country, ten in total. Finally, there is data from four lakes in the Philippines, which are located south of Manila near San Pablo City.