Westmoreland County · reservoir · 27 acres
Mammoth Lake
Stocked 5× on record · PFBC
Mammoth Lake is a reservoir in Westmoreland County, Pennsylvania, stocked with Golden Rainbow Trout and Rainbow Trout — most recently on Apr 21, 2026. FishableWaters aggregates every stocking record for this water from PFBC; the latest schedule and today's bite windows are above.
Best days this week
Days near a new or full moon tend to fish best.
Today's bite windows
Conditions, next 3 days
Today
Overcast
79°
59°
9 mph
0%
Fri
Overcast
82°
61°
6 mph
0%
Sat
Overcast
87°
69°
9 mph
24%
↗ pressure risingPost-front rising pressure can slow things down for a day.
Scheduled stockings ahead
Oct 13, 2026 — Rainbow Trout
Published schedule — agencies adjust for weather and water.
Stocking ledger
| — 2026 — | ||||
| Apr 21 | Rainbow Trout | — | ||
| Apr 10 | Rainbow Trout | — | ||
| Apr 10 | Golden Rainbow Trout | — | ||
| Mar 4 | Rainbow Trout | — | ||
| Mar 4 | Golden Rainbow Trout | — | ||
Angler reports
What's biting
No reports yet — be the first
Best bite times
No reports yet
Field notes
No notes yet
All Pennsylvania waters with golden rainbow trout → · All Pennsylvania waters with rainbow trout →
Nearby waters
- Loyalhanna Lake1.5 mi
- North Branch Sewickley Creek1.6 mi
- Welty Run2.0 mi
- County Reservoir2.8 mi
- Marguerite Reservoir3.8 mi
- Lonesome Lake3.7 mi
- Unity Reservoir5.2 mi
- Dry Ridge Reservoir5.2 mi
Seasons, limits, and rules are the state's call — check the official PA regulations and buy your license before you go. We link the source; we never restate the rules.
Mammoth Lake fishing — FAQ
What fish are stocked in Mammoth Lake?+
Mammoth Lake is stocked with Golden Rainbow Trout and Rainbow Trout in Westmoreland County, Pennsylvania, most recently on Apr 21, 2026 by PFBC. The full stocking ledger is on this page.
When does Mammoth Lake get stocked?+
Going by 5 records since 2026, stocking at Mammoth Lake peaks in April. Check this page for the season's scheduled and most recent stockings.
Do I need a license to fish Mammoth Lake?+
Yes — Pennsylvania requires a fishing license. Buy one from the state and check current seasons and limits before you go; both are linked on this page.
Where is Mammoth Lake?+
Mammoth Lake is a reservoir in Westmoreland County, Pennsylvania. Driving directions and an interactive topo map are on this page.
Data: PFBC · updated Apr 21, 2026 · checked daily · we publish what agencies publish, nothing else.