What are oligotrophic lakes in Wyoming?

20 oligotrophic lakes in Wyoming. Low nutrients, clear water, excellent for swimming.

What does oligotrophic mean?

Low nutrients, clear water, excellent for swimming.

Oligotrophic Lakes in Wyoming

An oligotrophic lake is what most people picture when they think of pristine northern lake country: clarity to depth, no algal scum, cold water that holds dissolved oxygen all the way to the bottom even in August. Across Wyoming, 20 lakes register as oligotrophic — 0% of them break 50 feet of depth, which is the structural condition that underwrites the trophic class. Without depth and a low-nutrient watershed, oligotrophy is hard to sustain.

On our A–F scale, oligotrophic lakes almost always pull an A or B — the same low-nutrient conditions that produce the trophic class also produce the high grade.

#	Lake	County	Grade	Clarity	Depth	TSI
1	Seminoe Reservoir Lacustrine Pelagic	Carbon	B	17.1 ft	-	40
2	Crystal Reservoir	Laramie	B	11.6 ft	-	40
3	Granite Springs Reservoir	Laramie	B	11.8 ft	-	39
4	Lake Desmet Lpd	Johnson	B	39.1 ft	-	31
5	Rob Roy Reservoir	Albany	B	11.2 ft	-	40
6	Half Moon Lake	Sublette	B	22.2 ft	-	35
7	Muddy Guard Reservoir	Johnson	B	15.2 ft	-	38
8	Lower New Fork Lake	Sublette	B	22 ft	-	35
9	Meadowlark Lake	Big Horn	B	11.7 ft	-	39
10	Boulder Lake	Sublette	B	27.7 ft	-	33
11	Lake Cameahwait	Fremont	B	11.6 ft	-	40
12	Fremont Lake	Sublette	B	42.8 ft	-	30
13	Morrison Reservoir	Platte	B	14.4 ft	-	38
14	Boysen Reservoir Transitional Embayment	Fremont	B	11 ft	-	40
15	Worthen Meadows Reservoir	Fremont	B	15.9 ft	-	37
16	West Newton Lake	Park	B	17.7 ft	-	37
17	Hog Park Reservoir	Carbon	B	17.9 ft	-	36
18	Hanna Reservoir	Carbon	B	-	-	37
19	Hanna Water Supply Lake	Carbon	B	-	-	37
20	Twin Lakes Reservoir D	Sheridan	B	-	-	37

All oligotrophic lakes →Minnesota version →Wisconsin version →Illinois version →Michigan version →Iowa version →Ohio version →Pennsylvania version →New York version →Missouri version →Indiana version →North Dakota version →South Dakota version →Florida version →Colorado version →North Carolina version →Vermont version →Texas version →Oregon version →Arkansas version →Oklahoma version →Kansas version →Nebraska version →Nevada version →Arizona version →Idaho version →Montana version →New Mexico version →Tennessee version →Alabama version →Virginia version →Kentucky version →Utah version →Washington version →Georgia version →Massachusetts version →Ontario version →Québec version →Nova Scotia version →British Columbia version →Newfoundland and Labrador version →All Wyoming lakes →

Source: EPA National Aquatic Resource Surveys, 2026.