Alberta

Castle River

Alberta·Southwest Alberta·49.44° N, 114.32° W

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About Castle River

The Castle starts as two forks in the Castle Parks. The West Castle comes down beside Highway 774 from Castle Mountain Resort, the South Castle comes down its own valley from the Waterton side, and they meet at the Castle River Bridge campground. From there the river runs north past Castle Falls, picks up the Carbondale, and turns east past Beaver Mines through ranch country to the Oldman Reservoir. Up top it is a clear, cold freestone where westslope cutthroat rise to dry flies and bull trout hold in the deeper pools. Lower down, rainbows and cutbows take over and whitefish get more common. The whole river is closed from November 1 to June 15, so it is a summer and fall river only.

Runoff runs long here. The river usually rises in May, stays high and brown through June, and often is not clear until mid-July. Read the Beaver Mines gauge for the river below the Carbondale. Above about 25 m³/s (880 cfs) it is blown out, it clears on the drop through 15 m³/s (530 cfs), and about 3 to 10 m³/s (105 to 355 cfs) is the late-July to September window, clear and wadeable at the tailouts. The Ranger Station gauge, just below the forks, reads about half that water and runs only from about March to October. Expect stoneflies in early July, PMDs through midsummer, caddis in the evenings, hoppers from August, and blue-winged olives on cloudy fall afternoons. A stimulator with a beadhead dropper covers most days.

The rules change by fork, so read them before you go. The mainstem lets you keep 2 trout over 35 cm (14") until August 31. The South Castle, the West Castle and the Carbondale are catch and release for trout all season, and every trout on the river goes back from September 1. Bull trout are zero everywhere in Alberta. The upper river sits in Castle Provincial Park, public land with campgrounds at Castle River Bridge and Castle Falls. Below the park the banks turn to private ranch land, so reach the water at bridges and road allowances and stay below the high-water mark, or ask the landowner. This is grizzly country, so carry bear spray. And when the Bow runs warm and low in July or August, Alberta can close every ES1 stream from 2 pm to midnight, the Castle included, so check the advisories before a summer trip.

Species

Westslope Cutthroat Trout
Primary (upper river and forks) · Jul-Sep · 10-15", a few larger
Native, and listed as Threatened. The purest fish live in the South Castle and West Castle headwaters, and the mainstem holds many cutbows. Trout are catch and release on the forks. On the mainstem you may keep cutthroat over 35 cm until August 31, but most anglers let them go.
Rainbow Trout
Common (lower river) · Jul-Oct · 10-16"
More common the farther downstream you go, and the main catch below Beaver Mines. On the mainstem you may keep rainbows over 35 cm until August 31.
Cutbow Trout
Common · Jul-Sep · 10-16"
Cutthroat and rainbow hybrids, found through the mainstem. They count as trout for the limit.
Mountain Whitefish
Common · Jul-Oct · 10-16"
Native and found through the mainstem, more of them lower down. You may keep 5 over 30 cm on the mainstem, the South Castle and the Carbondale until August 31, and none on the West Castle.
Bull Trout
Present (protected) · Release only · 16-26"
Native and listed as Threatened. They hold in the deeper pools and take streamers late in the season. Zero harvest in Alberta. Keep them in the water and release them quickly.

Species	Abundance	Best Season	Size
Westslope Cutthroat Trout	Primary (upper river and forks)	Jul-Sep	10-15", a few larger
Rainbow Trout	Common (lower river)	Jul-Oct	10-16"
Cutbow Trout	Common	Jul-Sep	10-16"
Mountain Whitefish	Common	Jul-Oct	10-16"
Bull Trout	Present (protected)	Release only	16-26"

Sections

4 reaches

Beaver Mines to Highway 3

WadeCutthroat · Rainbow Trout · Whitefish

The lowest and warmest reach, through ranch land toward the Oldman Reservoir, read at the Beaver Mines gauge at its top. Rainbow trout and mountain whitefish carry the catch, with fewer westslope cutthroat trout than upstream. Both banks are mostly private: use the Township Road 7-0 bridge and road allowances, stay below the high-water mark, or ask the landowner. On hot August days fish it early. The mainstem rules end at the Highway 3 bridge. Below it the river follows the Oldman Reservoir rules, open all year.

Best for: Rainbow trout and mountain whitefish for anglers who sort out access first, from late July into October.

Carbondale to Beaver Mines (Highway 507)

WadeCutthroat · Cutbow · Bull Trout · Rainbow Trout · Whitefish

Bigger water once the Carbondale joins, with longer runs and deeper pools as the river bends east toward Beaver Mines. The Beaver Mines gauge sits near the bottom of this reach. Rainbow trout and cutbows get more common here, along with westslope cutthroat trout, mountain whitefish and bull trout. The river leaves the park in this reach, and the banks below it are a mix of public and private land. Walk in at the Highway 507 bridge or the Township Road 6-3 bridge northeast of Beaver Mines and stay below the high-water mark.

Best for: Dry-dropper and nymph water for rainbow trout and cutbows in August and September, and a streamer for a bull trout in the fall.

Castle River Bridge to the Carbondale (Castle Falls)

WadeCutthroat · Cutbow · Bull Trout · Rainbow Trout · Whitefish

The mainstem starts where the West Castle joins beside Highway 774, and the Ranger Station gauge sits just below. It runs north through Castle Provincial Park past the Castle River Bridge and Castle Falls campgrounds, with riffles, pocket water and pools that wade easily at summer flows. Westslope cutthroat trout and cutbows carry the catch, with rainbow trout, mountain whitefish and bull trout in the deeper water. It is all public park land. The West Castle itself is a small cutthroat stream along the highway, catch and release for trout and whitefish from June 16 to October 31.

Best for: Dry-fly days for westslope cutthroat trout and cutbows from mid-July into September, with a campsite on the water.

South Castle (Castle Wildland)

WadeCutthroat · Bull Trout · Rainbow Trout · Whitefish

The upper Castle above the West Castle confluence, which the regulations and local anglers call the South Castle. It is small, clear water in Castle Wildland Provincial Park that holds westslope cutthroat trout, a few bull trout and mountain whitefish. Trout are catch and release here all season, and its headwaters are federal critical habitat for westslope cutthroat. You reach it by a gravel road and then trail up the valley, so expect a walk and few other anglers. No gauge reads it alone. The Ranger Station gauge, just below the forks, reads it together with the West Castle.

Best for: A day on foot for wild westslope cutthroat trout on dries, mid-July to September.

At a glance

Ideal wading flow: 3–10 m³/s
Blow-out: >25 m³/s
Ideal water temp: 10–16°C

Best seasons

Read at the Beaver Mines gauge for the river below the Carbondale. Runoff usually runs from May through June and into early July, above about 25 m³/s (880 cfs), high and brown. It clears on the drop through 15 m³/s (530 cfs), usually in mid-July, when the edges fish with stoneflies and nymphs. About 3 to 10 m³/s (105 to 355 cfs) is the late-July to September window, clear and crossable at the tailouts. Under about 3 m³/s (105 cfs) in a dry September the fish get spooky, so go small and long. For the river above the Carbondale, read the Ranger Station gauge just below the forks: it clears below about 8 m³/s (280 cfs), and about 1.5 to 5 m³/s (55 to 175 cfs) is the summer sweet spot. That gauge stops at the end of October. Trout feed best at about 10 to 16 °C (50 to 61 °F). No Castle gauge reports water temperature, so carry a thermometer and stop above 20 °C (68 °F).

Regulations

The Castle is in Alberta's ES1 watershed unit, with bait banned and the river closed November 1 to June 15. The mainstem is open June 16 to October 31, with 2 trout over 35 cm allowed until August 31 and everything released after. The South Castle, West Castle and Carbondale forks are catch and release for trout all season.

Castle River mainstem from Highway 3 up to the West Castle River, with tributaries except Mill, Beaver Mines and Screwdriver creeks and the Carbondale River: open June 16 to August 31, bait ban, mountain whitefish 5 over 30 cm, trout 2 (rainbow and cutthroat over 35 cm).
Same reach, September 1 to October 31: bait ban, mountain whitefish 0, trout 0.
Castle River downstream of Highway 3, part of the Oldman Reservoir listing: open all year, bait ban, mountain whitefish 5 over 30 cm, trout 5.
South Castle River, with tributaries: open June 16 to August 31, bait ban, mountain whitefish 5 over 30 cm, trout 0. September 1 to October 31: bait ban, mountain whitefish 0, trout 0.
West Castle River, with tributaries: open June 16 to October 31, bait ban, mountain whitefish 0, trout 0.
Carbondale River, with tributaries: open June 16 to August 31, bait ban, mountain whitefish 5 over 30 cm, trout 0. September 1 to October 31: bait ban, mountain whitefish 0, trout 0.
Mill Creek, Beaver Mines Creek and Screwdriver Creek do not follow the Castle's rules. Check the guide before you fish them.
Bull trout limit 0 everywhere in Alberta.
From July 1 to August 31 the province can close ES1 flowing waters from 2 pm to midnight when the Bow runs warm and low. Check mywildalberta.ca before a summer trip.
You need a WiN number and an Alberta sportfishing licence, sold through AlbertaRELM.

Any period not listed is closed. Bait ban means unscented lures and flies only. Bull trout and westslope cutthroat are both listed as Threatened, so release them quickly and keep them in the water. Below the Highway 3 bridge the Castle falls under the Oldman Reservoir rules, which the guide lists in the ES1 lakes table: open all year, bait ban, mountain whitefish 5 over 30 cm, trout 5. Alberta allows travel below the ordinary high-water mark of a river bounded by private land, but you need the landowner's permission to cross private land to reach it.

Source: 2026 Alberta Guide to Sportfishing Regulations (ES1). Regulations change annually. Verify before fishing.

Getting there

Pincher Creek, AB

About 20 minutes from Pincher Creek to Beaver Mines, and about 40 minutes to the Castle River Bridge campground by Highway 507 and Highway 774. About 2 hr 30 min from Calgary to Beaver Mines, and about 1 hr 15 min from Lethbridge. Calgary International Airport is the nearest large airport.

Camping: Alberta Parks campgrounds at Castle River Bridge and Castle Falls sit on the river and take reservations. Lynx Creek on the Carbondale is first come, first served, and Castle Provincial Park also has designated camping areas and cabins at Castle River Bridge. Pincher Creek has motels.

Highway 774 runs from Beaver Mines past Castle River Bridge to Castle Mountain Resort, with the West Castle beside it. The South Castle valley is reached by a gravel road and then trail in Castle Wildland Provincial Park. Summer off-highway vehicle use is being phased out of the Castle Parks, so check the Alberta Parks Castle trail report for what is open. Below the park the Castle runs through private ranch land: reach the water at bridges and road allowances and stay below the high-water mark, or ask the landowner. Carry bear spray.

Castle River

Alberta·Southwest Alberta·49.44° N, 114.32° W

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Fishing: Good
Flow: 3.6m³/s; Steady · normal; Castle River near Beaver Mines
Water temp: —

Flow

3.6m³/s

Steady ·

Castle River near Beaver Mines

Water temp

—

Normal range

2.9–7.2m³/s

Median 4.3 m³/s

Weather

8°C

Partly Cloudy