The goal of this project was to inventory the diatom flora of State Parks located in southwestern Pennsylvania. For the last few years this region has been experiencing a rapid increase in natural gas production. Protecting the health of lakes and rivers is an issue of growing importance in shale gas regions and documenting the current state of the aquatic biota is crucial for any future assessments of human impacts. The diatoms play a major role in aquatic ecosystems and are sensitive and widely used indicators of water quality. Collecting baseline data on the composition of diatom communities in State Parks in southwestern Pennsylvania is an important step towards monitoring environmental health in the region. 153 diatom samples have been collected from in various habitats, such as streams, lakes, and wetlands in twelve State Parks.