What is the cleanest lake in St. Lawrence County, New York?

Upper Lake in St. Lawrence County is the highest-rated lake in St. Lawrence County, New York with an EPA water quality grade of NR.

How are these rankings calculated?

Lakes are graded A through F on nutrients and algae — total phosphorus, nitrogen, chlorophyll-a, and turbidity — against EPA National Lakes Assessment 2022 condition classes for that lake’s ecoregion. Water clarity (Secchi depth) is measured and shown; it is not the letter. Lakes without enough recent samples are UNRATED, not given an F. Source data comes from the EPA Water Quality Portal.

Cleanest Lakes in St. Lawrence County, New York

Upper Lake in St. Lawrence County leads the rankings with a water quality grade of NR. Below are the top 50 cleanest monitored lakes in St. Lawrence County, New York, ranked by EPA water quality score.

Ranked List

#	Lake	County	Grade	Clarity	Phosphorus	Algae
1	Upper Lake	St. Lawrence	NR	-	-	-
2	Lake Ozonia	St. Lawrence	NR	-	-	-
3	Weller Pond	St. Lawrence	NR	-	-	-
4	Sterling Pond	St. Lawrence	NR	-	-	-
5	Clear Pond	St. Lawrence	NR	-	-	-
6	Five Falls Reservoir	St. Lawrence	NR	-	-	-
7	South Colton Reservoir	St. Lawrence	NR	-	-	-
8	Rainbow Falls Reservoir	St. Lawrence	NR	-	-	-
9	Joe Indian Pond	St. Lawrence	NR	-	-	-
10	Blake Falls Reservoir	St. Lawrence	NR	-	-	-
11	Barney Pond	St. Lawrence	NR	-	-	-
12	Stark Falls Reservoir	St. Lawrence	NR	-	-	-
13	Kildare Pond	St. Lawrence	NR	-	-	-
14	Jordan Lake	St. Lawrence	NR	-	-	-
15	Amber Lake	St. Lawrence	NR	-	-	-
16	Deer Pond	St. Lawrence	NR	-	-	-
17	Windfall Pond	St. Lawrence	NR	-	-	-
18	Catamount Pond	St. Lawrence	NR	-	-	-
19	Massawepie Lake	St. Lawrence	NR	-	-	-
20	Horseshoe Pond	St. Lawrence	NR	-	-	-
21	Long Pond	St. Lawrence	NR	-	-	-
22	Town Line Pond	St. Lawrence	NR	-	-	-
23	Deer Pond	St. Lawrence	NR	-	-	-
24	Jocks Pond	St. Lawrence	NR	-	-	-
25	Sampson Pond	St. Lawrence	NR	-	-	-
26	Grass River Flow	St. Lawrence	NR	-	-	-
27	Pleasant Lake	St. Lawrence	NR	-	-	-
28	Clear Pond	St. Lawrence	NR	-	-	-
29	Chandler Pond	St. Lawrence	NR	-	-	-
30	Leonard Pond	St. Lawrence	NR	-	-	-
31	Crooked Lake	St. Lawrence	NR	-	-	-
32	Carry Falls Reservoir	St. Lawrence	NR	-	-	-
33	Long Pond	St. Lawrence	NR	-	-	-
34	Pine Marsh	St. Lawrence	NR	-	-	-
35	Tracy Pond	St. Lawrence	NR	-	-	-
36	Tooley Pond	St. Lawrence	NR	-	-	-
37	Cook Pond	St. Lawrence	NR	-	-	-
38	Moosehead Pond	St. Lawrence	NR	-	-	-
39	Greenfield Pond	St. Lawrence	NR	-	-	-
40	Long Pond	St. Lawrence	NR	-	-	-
41	Round Pond	St. Lawrence	NR	-	-	-
42	Portaferry Lake	St. Lawrence	NR	-	-	-
43	Boyd Pond	St. Lawrence	NR	-	-	-
44	Clear Lake	St. Lawrence	NR	-	-	-
45	Warm Brook Flow	St. Lawrence	NR	-	-	-
46	Arbuckle Pond	St. Lawrence	NR	-	-	-
47	Green Pond	St. Lawrence	NR	-	-	-
48	Lower Lake	St. Lawrence	NR	-	-	-
49	Hickory Lake	St. Lawrence	NR	-	-	-
50	Mud Lake	St. Lawrence	NR	-	-	-

Ranked List

More Answers for St. Lawrence County, New York