| Reservoir length | 18 miles |
| Reservoir depth (max) | 151 feet |
| Reservoir depth (avg) | 45 feet |
| Shoreline (without islands) | 118 miles |
| Island shoreline | 63 miles |
| Reservoir capacity | 412 billion gallons |
| Reservoir surface area | 24,529 acres |
| Top one inch when full | 750 million gallons |
| Area of watershed | 119,940 acres |
| Area of Prescott Peninsula | 12,300 acres |
| Area of islands | 3,500 acres |
| Highest watershed elevation (Prospect Hill, Phillipston) | 1,383 feet |
| Reservoir elevation when full, Boston City base (BCB) | 530 feet |
| Towns in watershed | Athol, Barre, Belchertown, Hardwick, New Salem, Orange, Pelham, Petersham, Phillipston, Shutesbury, Ware, Wendell |
| Swift River release (legal requirement) | 20 million gallons/day |
| Average annual precipitation | 44 inches |
| Average precipitation yield to reservoir | 50% |
| Average reservoir gain from 1 inch precipitation | 1.6 billion gallons |
