Lakes / Massachusetts / Middlesex County / South Reservoir
South Reservoir, Massachusetts
79.62 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Massachusetts
42.45 degrees N, 71.12 degrees W - Middlesex County. State and county outlines drawn from Census boundary data; the lake marker is placed by its Massachusetts Division of Fisheries and Wildlife coordinates, not by eye. Schematic - not a survey map.
How South Reservoir Stacks Up
- Larger than 60% of the 784 lakes counted in Massachusetts.
- About 5 miles from Cambridge, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Middle Reservoir | Middlesex | 0.6 mi | 55.65 acres |
| North Reservoir | Middlesex | 1.1 mi | 59.44 acres |
| Spot Pond | Middlesex | 1.2 mi | 298 acres |
| Wedge Pond | Middlesex | 1.4 mi | 24 acres |
| Upper Mystic Lake | Middlesex | 1.8 mi | 178 acres |
| Lower Mystic Lake | Middlesex | 2.1 mi | 92.91 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About South Reservoir
How Big Is South Reservoir?
South Reservoir covers 79.62 acres in Middlesex County, Massachusetts.
What Is the Largest Lake in Middlesex County?
Whitehall Reservoir is the largest lake in Middlesex County, at 620 acres.
Deepest Natural Lakes in Massachusetts
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Walden Pond | Middlesex | 62 acres | 100 ft |
| 2 | Cliff Pond | Barnstable | 206 acres | 96 ft |
| 3 | Wallum Lake | Worcester | 322 acres | 81 ft |
| 4 | Onota Lake | Berkshire | 653 acres | 72 ft |
| 5 | Ashumet Pond | Barnstable | 220 acres | 69 ft |
All 211 Massachusetts lakes ranked by depth
Largest Lakes in Massachusetts
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Quabbin Reservoir | Franklin | 24,012 acres | - |
| 2 | Wachusett Reservoir | Worcester | 4,041 acres | - |
| 3 | Assawompset Pond | Plymouth | 2,652.37 acres | - |
| 4 | Watuppa Pond | Bristol | 1,758.37 acres | - |
| 5 | South Watuppa Pond | Bristol | 1,460 acres | 23 ft |
All 784 Massachusetts lakes ranked by surface area
Sources: USGS National Hydrography Dataset (The National Map) lake data (ID 135695078). Verified October 30, 2026.