This dataset presents mercury (Hg) and methylmercury (MeHg) concentration data in waters (surface river water and community drinking water), biota, plant, and sediments that were collected across eight communities along the Pra and Ankobra Rivers in Western Ghana. Water and sediment samples were collected in October 2024 from eight rivers along the Ankobra and Pra Rivers, two rivers heavily impacted by artisanal-scale gold mining (ASGM) activity. Fish and plant samples were obtained from the communities when available as samples of opportunity. This project was a part of the Embassy Science Fellowship program coordinated by the U.S. State department and all samples were collected in collaboration with the USGS Mercury Research Laboratory (MRL), the U.S. Embassy in Ghana, and Hen Mpoano, a non-governmental organization in Ghana. All samples were processed and analyzed at the USGS MRL in Madison, Wisconsin, USA.