Mono Pass to Grinnell Lake and Pioneer Basin
Trip Breakdown
Difficultly Rating: Moderate Days/Nights: 4/3 Distance: 32.34 mi
Elevation Range: 8,763' to 12,046' Total Elevation Gain/Loss: +8,649'/-8,649'
The Good: Easy pass; Great trout fishing
The Bad: Bugs along Mono Creek; Steep route up Laurel Creek
Marmot sightings: 0
Largest lake in Pioneer Basin.
A Brief Trail Preview
This Mono Pass (not be confused with the other Mono Pass on the border of Yosemite National Park) begins in Mosquito Flat at the end of Rock Creek Road. The Mono Pass Trail quickly peels off from the Little Lakes Valley Trail from the parking lot.
On this trip, we went over the pass (12,040’) and followed Mono Creek to the Grinnell Lake area and Pioneer Basin.
Route map.
Trail Dairy
We got a late start after work (as you can during the height of summer) and hit the trail around 6pm with a short objective for the day - camp at Ruby Lake. The trail from the trailhead to Ruby is a easy and beautiful jaunt, one we often trail run when we stay in Mammoth. Ruby Lake was obviously packed when we arrived close to sunset and we struggled to find a cleared spot to camp. We settled in, cooked dinner, and enjoyed our nightcap of choice - little 100ml canned Old Fashioneds called Slow & Low.
The next morning we had coffee and breakfast and set off for the pass. From Ruby Lake, we climbed a series of sandy switchbacks into the alpine zone and it was gradual to Summit Lake. The views to the south of the pass are incredible displays of granite. We made our way down to larger of the two Trail Lakes, passing a mule train on the way. There is a handsome backcountry hut at the larger Trail Lake used as a snow survey shelter.
After a few more switchbacks and a crossing of Golden Creek, we leveled off in the valley where Golden Creek converges with Mono Creek. This section in the forest was dusty and we were swarmed by flies thanks to all the mule dung on the trail. The silver lining was the incredible showing of wildflowers lining the trail in mid July as the trail opened up into a meadow along Mono Creek. We stopped for lunch at a little beach along the creek, sticking our legs in to cool off on this 80+ degree day in the Sierras before our climb up the Laurel Creek drainage towards Grinnell Lake.
The route up the Laurel Creek drainage was very steep, making our final push for the day a slog. But boy were we rewarded when the trail leveled off and opened up to an expansive views of the Silver Divide. We found a campsite perched above the the creek and dropped our packs to go explore Grinnell Lake. There is a loose trail to the lake but we ended up just making our own way. This secluded lake is an oasis, with crystal clear water backed by the dramatic metamorphic rock of Red and White Mountain.
We spent the rest of the evening fly fishing Laurel Creek, brimming with little fingerling brookies. We felt so fortunate to have this little slice of Sierra heaven to ourselves (minus the mosquitoes) that night.
The next morning we hiked back to Mono Creek and made our way towards Pioneer Basin, the main objective of most going over Mono Pass. The flies were flying and we stopped at the same spot at the creek again cause it was just that good. We were grateful that the hike into Pioneer Basin was much mellower than up Laurel Creek. The first lake was already occupied by a group, so we pushed on to the largest of the lakes in the basin. We set up camp perch with epic views to the north and south. We went for a dip, fly fished, and went on a side quest to the bowl below Mount Hopkins where there was in fact no lake this year, whoops!
iNaturalist Drama:
After our trip, I uploaded a few trout we caught to iNaturalist and sparked a heated debate between trout experts on a possible golden-rainbow hybrid.
We spent our last night watching the sunset from our perch, with Tanner running back and forth to capture the colors on the basin and over the valley below. Before bed, we made sure every item of ours was secure due to the basins large population of fearless, food-conditioned Belding’s ground squirrels. Thankfully when we woke up, everything was still intact. We started our hike out early the next morning and made it back to our car at Little Lakes Valley trailhead by lunch.
Before our long drive home, we have a tradition of hopping in a creek or lake so we stink less. Rock Creek Lake served the purpose well and we pit stopped at Rock Creek Lakes Resort for lunch. This is hands down my favorite post-backpacking lunch spot. Can’t beat barbeque, local craft brews, and Pie à la Mode (highly recommend the local apricot pie).
Route elevation info.
