ABSTRACT The Nygard index can be used to determine the trophic state of waters. Nygaard Index calculation is based on the number of phytoplankton species include in the following groups, that is Chlorococcales, Euglenophyceae, Centric Diatoms, Myxophyceae and Desmidiaceae. This study aims to determine the trophic state of Parit Lake based on the Nygaard Index. This research was conducted i…