This Groundwater Management Plan has been prepared by the Susquehanna River Basin Commission (Commission) under the general oversight of its Water Resources Management Advisory Committee (WRMAC). A critical and long-term part of the Commission's mission, as reflected in the 1971 Susquehanna River Basin Compact (Compact), is the achievement of a balance among environmental, human, and economic needs in the management of the basin's water resources. The recommended water resource management actions in the plan were formulated with the goal of balancing economic development and environmental protection as a primary consideration. This was achieved by carefully considering: (1) sustainability of the resources for future generations; (2) protection of existing users; (3) adverse environmental impacts and actions to minimize the impacts; (4) protection of high quality water from degradation; (5) effective interagency coordination; and (6) public understanding of groundwater issues. The plan also represents a comprehensive revision to the Commission's first Groundwater Management Plan, which was prepared in 1993. Appendix E of this report contains the list of the 1993 plan recommendations, which have either been implemented or are not relevant today. There were 37 additional recommendations identified in the 1993 plan that have not been implemented, and those served as an initial basis for the updated management plan.