Lakes / Montana / Valley County

Lakes in Valley County, Montana

31 lakes counted in Valley County - the largest is Fort Peck Lake at 233,053 acres.

Lakes Counted

233,053 acres

Largest - Fort Peck Lake

Valley County, highlighted, with its largest counted lakes dotted. Outlines from Census boundary data.

All Counted Lakes

#	Lake	County	Surface Area	Max Depth
1	Fort Peck Lake	Valley	233,053 acres	-
2	Triple Crossing Reservoir	Valley	394.6 acres	-
3	Frazer Lake	Valley	310 acres	-
4	Grub Detention Reservoir	Valley	229.3 acres	-
5	VR-2 Reservoir	Valley	180.6 acres	-
6	Mahan and Hoyt Reservoir	Valley	170.5 acres	-
7	Todd Lakes	Valley	104.5 acres	-
8	Lake Grable	Valley	89.2 acres	-
9	Jim Reservoir	Valley	82 acres	-
10	Cactus Flat Detention Reservoir	Valley	66 acres	-
11	South Beaver Reservoir	Valley	64.7 acres	-
12	Collins Reservoir	Valley	58.1 acres	-
13	Fort Peck Trout Pond	Valley	53 acres	-
14	Target Detention Reservoir	Valley	49.4 acres	-
15	Gutshot Detention Reservoir	Valley	43.7 acres	-
16	Cornwell Reservoir	Valley	43.5 acres	-
17	Arrambide Reservoir	Valley	41.8 acres	-
18	Corral Junction Number Two Detention Reservoir	Valley	37.6 acres	-
19	Lori Detention Reservoir	Valley	34.6 acres	-
20	Itcaina Reservoir	Valley	34.1 acres	-
21	Baalke Slough	Valley	33.6 acres	-
22	Willow Creek Flat Reservoir	Valley	32.9 acres	-
23	Forrest Reservoir	Valley	31.6 acres	-
24	Halfpint Reservoir	Valley	30.4 acres	-
25	Willow Flat Reservoir	Valley	26.4 acres	-
26	Forsman Reservoir	Valley	20 acres	-
27	Valley Reservoir	Valley	11 acres	About 12 ft
28	O'Juel Lake	Valley	10 acres	-
29	Luther Reservoir	Valley	9 acres	-
30	Paul Reservoir	Valley	9 acres	-
31	Whitetail Reservoir	Valley	7 acres	-

Sources: Montana Fish, Wildlife & Parks lake data; USGS. Verified October 30, 2026.