Mammoth Creek (Iron County) fishing
Mammoth Creek was last stocked on June 4, 2025 with 1,000 tiger trout (3.4 in. average), according to the Utah DWR fish stocking report. It is a river or stream in Iron County, Utah. From 2021 to 2026, DWR stocked 46,477 fish here, the 4th most of 23 stocked waters in Iron County.
Recent stockings at Mammoth Creek
- June 4, 20251,000 tiger trout, 3.4 in. average
- May 21, 20251,020 tiger trout, 9.9 in. average
- Sept. 11, 20238,066 cutthroat trout, 1.9 in. average
- Sept. 12, 202212,359 cutthroat trout, 2.0 in. average
- June 15, 2022512 tiger trout, 8.7 in. average
- Sept. 16, 20219,250 cutthroat trout, 2.3 in. average
Newest first, from the Utah DWR stocking report. Full stocking history.
Mammoth Creek facts
- Last stocked
- June 4, 2025 (524 days ago): 1,000 tiger trout
- Stockings in 2026
- None recorded yet in 2026
- County
- Iron County
- Stocked since 2021
- tiger trout and cutthroat trout
- Average size stocked
- 2.8 in. (2021 to 2026)
- County rank
- 4th most fish of 23 stocked waters in Iron County since 2021
- Name in DWR report
- MAMMOTH CR
- Nearest water
- Louder Ranger Station, 1.1 mi
- Rules
- Statewide rules (no water-specific entry in the 2026 guidebook)
Mammoth Creek stocking report, last 12 months
No stocking recorded in the last 12 months. The most recent record is dated June 4, 2025.
Source: Utah DWR fish stocking report. Stocking data fetched Nov. 10, 2026; newest record dated Nov. 19, 2026. DWR posts stockings after they happen and does not publish schedules.
Mammoth Creek stocking profile
- First record in the DWR report: June 15, 2021. Since then DWR has logged 10 stockings here in 4 different years, 46,477 fish in all.
- Species stocked 2021 to 2026, by share of fish: cutthroat trout 87% (40,635 fish) and tiger trout 13% (5,842 fish).
- Busiest months in the record: June (30% of records) and September (30% of records).
- Stocked fish averaged 2.8 in. from 2021 to 2026 (per-record averages ranged from 1.7 to 10.2 in.). The yearly average was 3.1 in. in 2021 and 6.7 in. in 2025.
- Fish stocked 2021 to 2026: 46,477, the 4th most of 23 stocked waters in Iron County and 120th of 1,076 statewide.
- Nearest other water with a page: Louder Ranger Station, 1.1 mi away.
- Other water with this name: Mammoth Creek in Garfield County, 8 mi away. DWR lists them as separate waters (DWR water ids VIAA780-04 and VIAA780-03).
Computed from Utah DWR stocking records (fish counts and average lengths as DWR reports them). Past stocking is history, not a schedule.
When is Mammoth Creek stocked?
Based on DWR stocking records, 2021 to 2025. Stocked in 4 of those 5 years.
2025 stocking: 2 records, first on May 21, last on June 4.
In past years, stocking here had usually started by this time of year (4 of the last 5 years). No stocking has been recorded here yet in 2026.
DWR does not publish stocking schedules. This is past stocking, not a promise. How we read patterns.
Mammoth Creek stocking history by year
| Year | Records | Fish | Avg. length | Species |
|---|---|---|---|---|
| 2025 | 2 | 2,020 | 6.7 in. | Tiger trout |
| 2023 | 1 | 8,066 | 1.9 in. | Cutthroat trout |
| 2022 | 2 | 12,871 | 2.3 in. | Cutthroat trout, Tiger trout |
| 2021 | 5 | 23,520 | 3.1 in. | Cutthroat trout, Tiger trout |
All stocking records 2021 to Nov. 10, 2025 (10)
| June 4, 2025 | Tiger trout | 1,000 | 3.4 in. |
| May 21, 2025 | Tiger trout | 1,020 | 9.9 in. |
| Sept. 11, 2023 | Cutthroat trout | 8,066 | 1.9 in. |
| Sept. 12, 2022 | Cutthroat trout | 12,359 | 2.0 in. |
| June 15, 2022 | Tiger trout | 512 | 8.7 in. |
| Sept. 16, 2021 | Cutthroat trout | 9,250 | 2.3 in. |
| Aug. 18, 2021 | Cutthroat trout | 10,960 | 1.7 in. |
| July 13, 2021 | Tiger trout | 1,449 | 9.8 in. |
| July 1, 2021 | Tiger trout | 1,557 | 9.5 in. |
| June 15, 2021 | Tiger trout | 304 | 10.2 in. |
Fishing rules
No water-specific entry for Mammoth Creek in the 2026 guidebook: statewide limits apply unless a group entry (such as a drainage) covers it.
From the 2026 Utah Fishing Guidebook, in our own words. Rules can change mid-year: check wildlife.utah.gov/guidebooks before fishing.
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Mammoth Creek questions
When is Mammoth Creek stocked?
DWR does not publish stocking schedules. Past records show Mammoth Creek was stocked in early to mid June (3 of the last 5 years) and mid September (3 of the last 5 years). The most recent stocking in the DWR report is dated June 4, 2025.
What fish are in Mammoth Creek?
Since 2021 DWR has stocked tiger trout and cutthroat trout.
Stocking: Utah DWR fish stocking report, fetched Nov. 10, 2026. Location: Utah DWR, USGS NHD. Rules: 2026 Utah Fishing Guidebook. Page built Nov. 10, 2026. Found an error? Tell us. Verify rules with DWR before fishing.