Lakes / Illinois / Pike County / Halfmoon Lake
Halfmoon Lake, Illinois
66.72 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Illinois
39.43 degrees N, 90.97 degrees W - Pike County. State and county outlines drawn from Census boundary data; the lake marker is placed by its USGS National Hydrography Dataset coordinates, not by eye. Schematic - not a survey map.
How Halfmoon Lake Stacks Up
- Larger than 48% of the 511 lakes counted in Illinois.
- About 74 miles from Springfield, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Log Slough | Pike | 0.7 mi | 28.91 acres |
| Han Slough | Pike | 1.4 mi | 50.66 acres |
| Upper Swan Lake | Pike | 1.5 mi | 99.09 acres |
| Towhead Lake | Pike | 1.9 mi | 67.21 acres |
| Twin Lakes | Pike | 2.8 mi | 49.17 acres |
| Horseshoe Lake | Pike | 8.4 mi | 146.78 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Halfmoon Lake
How Big Is Halfmoon Lake?
Halfmoon Lake covers 66.72 acres in Pike County, Illinois.
What Is the Largest Lake in Pike County?
Lake Pittsfield is the largest lake in Pike County, at 216.46 acres.
Largest Lakes in Illinois
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Carlyle Lake | Clinton | 22,796.77 acres | - |
| 2 | Mine Number 21 Reservoir | Franklin | 17,062.04 acres | - |
| 3 | Upper Peoria Lake | Woodford | 15,460.64 acres | - |
| 4 | Lake Shelbyville | Shelby | 10,235.1 acres | - |
| 5 | Crab Orchard Lake | Williamson | 7,292.57 acres | - |
All 511 Illinois lakes ranked by surface area
Sources: USGS National Hydrography Dataset (The National Map) lake data (ID 144568157). Verified October 30, 2026.