Lanark County Lake Quality

Ontario, 29 lakes, average grade A (Excellent)

Lanark County's 29 graded lakes fall in the moderate-density bracket for Ontario. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. On average, Lanark County lakes grade an A. That puts it near the top of the Ontario county ranking.

The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Black Lake (A); the most-stressed is Bowley Lake (C).

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Quick Answers for Lanark County

Cleanest lakes in Lanark County →Cleanest lakes in Ontario →Safest swimming lakes in Ontario →

Planning a trip? Check special fishing regulations for Black Lake — or check the official Ontario fishing regulations.

All Lakes in Lanark County

Rank	Lake	Grade	Clarity	Phosphorus
1	Black Lake	A	15.1 ft	-
2	Christie Lake	A	15.1 ft	9.5 µg/L
3	Davern Lake	A	17.1 ft	7.8 µg/L
4	Farren Lake	A	19 ft	10.5 µg/L
5	Flower Round Lake	A	19.7 ft	-
6	Obrien Lake	A	16.2 ft	8.8 µg/L
7	Otty Lake	A	16.4 ft	13.3 µg/L
8	Patterson Lake	A	17.4 ft	9.9 µg/L
9	Pike Lake	A	15.4 ft	11.1 µg/L
10	Robert'S Lake	A	15.3 ft	9 µg/L
11	Robertson Lake	A	27.9 ft	10.8 µg/L
12	Mann Lake	A	-	16.4 µg/L
13	Upper Park Lake	A	-	10.4 µg/L
14	Farrell Lake	A	20.7 ft	7.9 µg/L
15	Adam'S Lake	A	14.1 ft	13.2 µg/L
16	Bennett Lake	A	11.5 ft	9.3 µg/L
17	Izatt Lake	A	10.2 ft	13.6 µg/L
18	Little Silver Lake	A	14.8 ft	8.3 µg/L
19	Long Lake	A	13.5 ft	8.8 µg/L
20	Lower Rideau Lake	A	14.8 ft	16.4 µg/L
21	Mclaren Lake	A	10.2 ft	16.1 µg/L
22	Mississippi Lake	A	11.2 ft	12.5 µg/L
23	Rock Lake	A	11.5 ft	8.4 µg/L
24	Round Lake	A	12 ft	10 µg/L
25	White Lake	A	10.5 ft	10.4 µg/L
26	Dalhousie Lake	A	11.2 ft	9.2 µg/L
27	Murray Lake	B	7.9 ft	8.6 µg/L
28	Rainbow Lake	B	9.2 ft	13.8 µg/L
29	Bowley Lake	C	4.4 ft	27.5 µg/L