Lakes / Colorado / Larimer County / Portner Reservoir
Portner Reservoir, Colorado
49 acres
Surface Area
Where It Sits, and How Deep It Goes
Locator - Colorado
40.50 degrees N, 105.06 degrees W - Larimer 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 Portner Reservoir Stacks Up
- Larger than 42% of the 778 lakes counted in Colorado.
- About 36 miles from Boulder, as the crow flies.
Lakes Nearby
| Lake | County | Distance | Surface Area |
|---|---|---|---|
| Robert Benson Lake | Larimer | 1.4 mi | 50 acres |
| Warren Lake | Larimer | 2.0 mi | 142 acres |
| Duck Lake | Larimer | 2.4 mi | 35 acres |
| Donath Lake | Larimer | 2.7 mi | 85 acres |
| Fossil Creek Reservoir | Larimer | 3.0 mi | 669 acres |
| Nelson Reservoir | Larimer | 3.1 mi | 36 acres |
Straight-line distance between lake centers.
Facts and Figures
Questions About Portner Reservoir
How Big Is Portner Reservoir?
Portner Reservoir covers 49 acres in Larimer County, Colorado.
What Is the Largest Lake in Larimer County?
Horsetooth Reservoir is the largest lake in Larimer County, at 1,817 acres.
Largest Lakes in Colorado
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | John Martin Reservoir | Bent | 11,686 acres | - |
| 2 | Blue Mesa Reservoir | Gunnison | 8,944 acres | - |
| 3 | Lake Granby | Grand | 7,075 acres | - |
| 4 | Lake Meredith | Crowley | 5,539 acres | - |
| 5 | Adobe Creek Reservoir | Bent | 4,770 acres | - |
All 778 Colorado lakes ranked by surface area
Sources: USGS NHD (The National Map NHD MapServer layer 12) named waterbodies FTYPE 390/436; counties via Census point-in-polygon lake data (ID 128076435). Verified October 30, 2026.