Fishing in Jefferson County, Montana
County seat: Boulder. Census 2020 residents: 12,085.
- 1lake pages
- 3ramps
- 1river pages
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An overview of the Montana water in Jefferson County
A Census 2020 population of 12,085 makes up Jefferson County, governed from Boulder. The Census measures 1,657 square miles of land and 2.4 square miles of water inside the line. The county carries 1 lake or reservoir with write-ups; Whitetail Reservoir (Jefferson County) is biggest. Running water with its own page here includes Jefferson River.
Inside the county line sit 3 ramps and 2 other fishing sites that have no ramp. The 2026 book lists exception rules for 1 water in the county.
U.S. Census Bureau, 2020 Census counts (TIGERweb) and the 2023 Gazetteer, read November 12, 2026. FWP Fishing Access Sites layer (ArcGIS service) and the FishMT site pages, read November 12, 2026.
Pins for every Montana access site and lake in Jefferson County
FWP Fishing Access Sites layer (ArcGIS service) and the FishMT site pages, read November 12, 2026. Lake pins are the FWP reference point for each water.
Montana still water inside Jefferson County
| Lake | Size | Access sites | Kind | MFISH lists |
|---|---|---|---|---|
| Whitetail Reservoir (Jefferson County) | 603 acres | 0 | reservoir | Westslope cutthroat trout |
Out of Boulder, a drive over the Jefferson County line reaches these lakes.
| Lake | From Boulder | Size | Access sites | Kind | MFISH lists |
|---|---|---|---|---|---|
| Spring Meadow Lake | 26 miles north | about 14 acres of mapped outline | 0 | natural lake | largemouth bass, pumpkinseed, rainbow trout |
| Helena Valley Regulating Reservoir | 30 miles northeast | 553 acres | 1 | reservoir | burbot, kokanee salmon, yellow perch |
| Amc Settling Pond #1 | 31 miles west | 293 acres | 0 | pond | brown trout, rainbow trout |
| Amc Settling Pond #2 | 32 miles west | 526 acres | 0 | pond | brown trout, rainbow trout |
| Canyon Ferry Lake | 32 miles northeast | 33,535 acres | 0 | natural lake | brook trout, brown trout, burbot |
| Lake Helena | 33 miles north | 2,073 acres | 1 | natural lake | brown trout, burbot, mountain whitefish |
Size as the FWP FishMT page for this water prints it (FishMT), read November 12, 2026. Waters with no FishMT size print their mapped outline instead. Montana FWP Lakes reference layer (ArcGIS service) and the MFISH fish distribution layers, read November 12, 2026.
For the kokanee herePiscifun Carbon XT ultralight spinning reel25% OFFSale $59.99 The Montana presence tally for Jefferson County
Bars count lake pages within 60 miles of Boulder where the MFISH layer lists the fish; rainbow trout leads.
FWP MFISH presence layers, counted per lake page within 60 miles; presence in a layer, not a catch survey. FWP MFISH fish distribution layer (ArcGIS service), read November 12, 2026. Presence is mapping data, not a catch report.
Moving Montana water in Jefferson County
- Jefferson Riverexception rules, 10 access sites, 3 USGS gauges
Water-level stations inside Jefferson County
| USGS gauge | Latest reading | Time (ET) |
|---|---|---|
| Boulder River Near Boulder, Mt | 43 cfs, 5.23 ft gage height | Nov 15 4:15 pm |
| Prickly Pear Creek Near Clancy Mt | 23 cfs, 0.61 ft gage height | Nov 15 3:30 pm |
US Geological Survey provisional data, retrieved Nov 15, 2026 4:33 pm ET. Provisional readings can be revised.
Montana FWP MFISH stream layers (ArcGIS service) for this river, read November 12, 2026. USGS Water Data for the Nation, live through the site, retrieved on page view.
Montana launch ramps across Jefferson County
- Cardwell Bridge Fishing Access Site on Jefferson Riverfishing access site, ramp (gravel), gravel surface, 6 acres; Jefferson County
- Mayflower Bridge Fishing Access Site on Jefferson Riverfishing access site, ramp (concrete), concrete surface, 20 acres; Jefferson County
- Sappington Bridge Fishing Access Site on Jefferson Riverfishing access site, ramp (gravel), gravel surface, 1 acres; Jefferson County
Docks and piers in Jefferson County
- Limespur Fishing Access Site on Jefferson Riverfishing access site, no boat facilities, 106 acres; Jefferson County
- Piedmont Pond Fishing Access Sitefishing access site, no boat facilities, 21 acres; Jefferson County
FWP Fishing Access Sites layer (ArcGIS service) and the FishMT site pages, read November 12, 2026.
Little lakes of Jefferson County that carry only a name and outline
- Delmoe Lakeabout 279 acres of mapped outline
- Cottonwood Lakeabout 33 acres of mapped outline
- Park Lakeabout 33 acres of mapped outline
- Northern Pacific Reservoirabout 16 acres of mapped outline
- Glenwood Lakeabout 12 acres of mapped outline
- Keogh Reservoirabout 11 acres of mapped outline
Outline area from the FWP Lakes reference layer (ArcGIS service; mapped polygon area, not an FWP surface-acre figure), read November 12, 2026. Names come from the FWP Lakes reference layer; no page and no fish list for these waters.
Rule changes the book lists for Jefferson County waters
The rules here are from the 2026 Montana Fishing Regulations, valid March 1, 2026 through the end of February 2027; FWP had published no 2027 booklet when this was checked.
- Jefferson RiverNorthern pike: no limit. (JEFFERSON RIVER)
2026 Montana Fishing Regulations (valid March 1, 2026 through February 28, 2027; FWP PDF), read November 12, 2026.
Where Jefferson County shows up in the FWP record list
| Species | Weight or length as listed | Water | Year | Marked |
|---|---|---|---|---|
| Utah chub | 2.39 lbs. | Canyon Ferry Lake | 2022 | not marked native |
| Kokanee salmon | 7.85 lbs. | Hauser Reservoir | 2003 | not marked native |
| Longnose sucker | 4.78 lbs. | Hauser Reservoir | 2022 | native |
| Mountain whitefish | 5.11 lbs. | Hauser Reservoir | 2007 | native |
Montana state record fish as FWP lists them (records page), read November 12, 2026.
Gear stores in Jefferson County
Shops the Jefferson County regulars swear by
- L&P Grocerybait and tackle shop, Boulder
Montana guides listed near Jefferson County
- Fat Hat Drifters Inc.fishing guide, Clancy
Yellow Pages, State Parks and operator listings (city of business), read November 12, 2026. Guides are listed as businesses; no licence status is implied.
In Montana close to Jefferson County
Montana places in Jefferson County with town pages
- Montana City2020 count 2,918
- Boulder2020 count 1,201
- Whitehall2020 count 1,006
Montana neighbors of Jefferson County
- Broadwater County30 miles northeast
- Silver Bow County33 miles southwest
- Deer Lodge County52 miles west
- Madison County56 miles south
Piscifun reels and line to pack for a Montana trip to Jefferson County
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Montana banks and boat docks worth a frame near Jefferson County
Photo: Ken Lund, CC BY-SA 2.0
Photo: Mobilus In Mobili, CC BY-SA 2.0
Photo: Phil Price, CC BY-SA 2.0
Photo: Shawn Michael, CC BY 2.0
Fishing inside Jefferson County, Montana: the common asks
Where can I put a boat in the water in Montana's Jefferson County?
3 ramps, each in the access list above.
Which Montana lake is the biggest in Jefferson County?
Whitetail Reservoir (Jefferson County) leads with 603 acres.
What fish turn up on FWP pages near Jefferson County?
MFISH names rainbow trout on the most lake pages within 60 miles, then Westslope cutthroat trout, brook trout and brown trout; the layer shows presence, not a catch.
Where do Montana anglers in Jefferson County pick up flies and jigs?
1 listings, L&P Grocery among them.
What Montana town serves Jefferson County as its seat?
It is Boulder.
What does a Montana fishing license cost for Jefferson County?
Anglers 12 and older buy a Conservation License, an aquatic invasive species pass and a fishing license; the 2026 Montana Fishing Regulations prints $8, $2 and $21 for a resident full season and $10, $7.50 and $100 for a nonresident.
What Montana counties are closest to Jefferson County?
Nearest first: Broadwater County, Silver Bow County and Deer Lodge County.
What limits cover Jefferson County water?
Limits depend on the FWP fishing district and on any exception heading printed for the water; the Western, Central and Eastern district pages on this site give the charts. The rules here are from the 2026 Montana Fishing Regulations, valid March 1, 2026 through the end of February 2027; FWP had published no 2027 booklet when this was checked.
Does the regulation book list exceptions for Jefferson County water?
1 water with a page here carry their own exception lines, beginning with Jefferson River.
A prairie or Rockies morning in Jefferson County
River pages list access sites and live USGS flow.