This report contains the groundwater and surface water monitoring data that were obtained during calendar year (CY) 2001 at the U.S. Department of Energy (DOE) Y-12 National Security Complex (hereafter referenced as Y-12) in Oak Ridge, Tennessee. The monitoring data were obtained from groundwater and surface water sampling locations within three hydrogeologic regimes at Y-12. The following sections of this report provide details regarding the CY 2001 groundwater and surface water monitoring activities in the Bear Creek, East Fork, and Chestnut Ridge Regimes. Section 2 identifies the sampling locations in each hydrogeologic regime and the corresponding sampling frequency during CY 2001, along with the associated quality assurance/quality control (QA/QC) sampling. Section 3 describes groundwater and surface water sample collection and Section 4 identifies the field measurements and laboratory analytes for each sampling location. Section 5 outlines the data management protocols and data quality objectives (DQOs). Section 6 describes the groundwater elevation monitoring in each regime during CY 2001 and Section 7 lists the documents cited for more detailed operational, regulatory, and technical information.