When was Yellowtail Afterbay Reservoir last stocked?

The latest reported stocking was May 6, 2026 (rainbow trout, 6,239 fish), according to Montana agency reports.

How often is Yellowtail Afterbay Reservoir stocked?

It was stocked once in the last 12 months. Across all years on record, most stockings come in April.

Is Yellowtail Afterbay Reservoir stocked often?

Stocked more often than 77% of Montana waters on our record. We count each day the agency reported stocking it.

What kind of trout are stocked in Yellowtail Afterbay Reservoir?

Rainbow trout (3 stockings, 21,199 fish).

Yellowtail Afterbay Reservoir trout stocking

Big Horn County, Montana · lake · 3,188 ft elevation

Yellowtail Afterbay Reservoir was last stocked 6 months ago (May 6, 2026). We have 3 stockings on record since Apr 1, 2025, 1 in the last 12 months (6,239 fish). Most stockings come in April. Species stocked: rainbow trout.

Last stocked

6 months ago

May 6, 2026

Next planned

Not announced

Last 12 months

1 stocking

6,239 fish

On record

3 stockings

since Apr 1, 2025

Stocked more often than 77% of Montana waters on our record.

River conditions

USGS gage: Bighorn R bl Yellowtail Afterbay Dam nr St. Xavier (2 km away).

Flow: 1,630 cfs; about normal for the last six weeks
Gage height: 61.09 ft

Streamflow, last six weeks (cfs), daily. Latest: 1,630 cfs on Nov 8.

Latest reading Nov 9, 2026, 9:15 AM UTC. USGS data are provisional. Gage page at USGS.

Weather at Yellowtail Afterbay Reservoir

Tonight
39°F
Mostly Cloudy
1% rain · wind 2 to 8 mph
Monday
62°F
Mostly Sunny
1% rain · wind 2 to 6 mph
Monday Night
42°F
Mostly Cloudy
7% rain · wind 3 to 9 mph
Tuesday
61°F
Partly Sunny
7% rain · wind 8 to 17 mph
Tuesday Night
38°F
Partly Cloudy
wind 10 mph
Veterans Day
65°F
Sunny
wind 8 to 12 mph

Forecast from the National Weather Service for this location, refreshed hourly.

When is Yellowtail Afterbay Reservoir stocked?

Most stockings come in April.

By month, all years

Stockings of Yellowtail Afterbay Reservoir by month, all years on record. This month is shown in blue.

Year by year

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
2026					1
2025				2

What is stocked

Species	Stockings	Fish	Fish per stocking	Typical size
Rainbow trout	3	21,199	7,066	4.5 in

Stocking history

20261 stocking · 6,239 fish

Date	Species	Fish	Size	Since previous	Hatchery
May 6Latest Wednesday	Rainbow trout	6,239	5.1 in	57 weeks	Bluewater Springs Trout Hatchery

20252 stockings · 14,960 fish

Date	Species	Fish	Size	Since previous	Hatchery
Apr 2 Wednesday	Rainbow trout	6,649	4.5 in	1 day	Bluewater Springs Trout Hatchery
Apr 1 Tuesday	Rainbow trout	8,311	4.3 in		Bluewater Springs Trout Hatchery

From Montana fish and wildlife agency reports, collected nightly and kept after the agency takes them down. Agencies revise reports; check the agency's report before you go. Seasons and limits: Montana fishing regulations.

Where is Yellowtail Afterbay Reservoir?

Big Horn County, Montana. The marker is the agency's location for this water; streams are often stocked at several access points.

Directions Larger map Montana fishing regulations

Questions about Yellowtail Afterbay Reservoir

When was Yellowtail Afterbay Reservoir last stocked?: The latest reported stocking was May 6, 2026 (rainbow trout, 6,239 fish), according to Montana agency reports.
How often is Yellowtail Afterbay Reservoir stocked?: It was stocked once in the last 12 months. Across all years on record, most stockings come in April.
Is Yellowtail Afterbay Reservoir stocked often?: Stocked more often than 77% of Montana waters on our record. We count each day the agency reported stocking it.
What kind of trout are stocked in Yellowtail Afterbay Reservoir?: Rainbow trout (3 stockings, 21,199 fish).