Page Type Page Type: Mountain/Rock
Location Lat/Lon: 44.02135°N / 113.55425°W
Additional Information County: Custer
Activities Activities: Hiking, Mountaineering, Trad Climbing, Mixed, Scrambling
Seasons Season: Spring, Summer, Fall
Additional Information Elevation: 11332 ft / 3454 m
Sign the Climber's Log


Limestone Mountain Traverse
Situated in the southern section of the Lost River Range in an area of limestone towers upon limestone plateaus, this peak offers a challenging scramble.  In Tom Lopez's Idaho A Climbing Guide, he describes the summit ridge as the most rugged in the range.  He also reports that no one has claimed reaching the true summit from the south.   When approached from the Lower Cedar Creek drainage on the west and south sides, the peak displays an easily misleading false summit.  This lower south summit is easily reached via mostly Class 2 scrambling until a 10 foot vertical limestone band is ascended using an obvious notch. At the false summit there is a cairn and a nice view of the true summit to the north, and Ross Peak further to the north. To reach the true summit you must descend below the upper limestone plateau and make an exposed traverse over loose rock on the north side.  This ramp snakes over vertical cliff bands that drop off vertically.  Depending on the conditions, you may need to kick steps in snow (or loose rock) on this shaded north side. On the true summit is a small cairn and summit register.  This north side traverse is the only way from the Lower Cedar Creek approach without using hardware and ropes.  

Limestone Mountain s True Summit
From the summit, the views of the southern Lost River Range include Wet Peak, Hidden Peak, USGS Peak, Shadow Lake Peak, Sheephead Peak, and many of the 12ers in the distance to the northwest.  The rock in the area is a unique mixture of vertical limestone bands, arches, and impressive towers.  The rock varies greatly from incredibly solid and sharp limestone to a brittle and crumbly deteriorated limestone.  From the opening of Lower Cedar Creek to the summit involves ascending about 15 vertical cliff bands of solid rock. Most all of these are easily scrambled over in the weakness.  The most impressive of these bands occur on the south to east sides near the summit block and range in vertical height from 50-100 feet. 


Limestone Mountain Pinnacles


  1. South Ridge (Mostly Class 2 with some exposed Class 3 sections near the summit traverse)- For more detail see the Routes Page (5 Miles, 5009 foot elevation gain - one way)  
  2. North Ridge (Class 4)-  Scramble up from the upper reaches of Wet Creek past Nolan Lake to a prominent saddle between Ross Peak and Limestone Peak.  Climb the north ridge over mostly solid limestone to the summit.  (5 Miles, 3623 foot elevation gain - one way)  

Maps:  USGS Massacre Mountain

Getting There

Limestone Shelves

Limestone Mountain is hidden from view from most all roads. It's located 7.8 miles NNW of Mackay, Idaho and 4.8 miles due west of Pass Creek. Borah Peak, the range's tallest sits 13.8 miles northwest of Limestone Peak.

Road Approach

Off ID-93 in Mackay, Idaho follow Main Street east onto a dirt road until a sign is reached that says "Lower Cedar Creek".  Follow the dirt road north to the head of the canyon where there's a newer irrigation operation.  You'll have to drop into the canyon before you reach the trailhead.

USGS East Ridge

Hike / Scramble Approach

Follow a well used trail past some historic irrigation remnants. Initially you'll pass a newer gauging station, but as you continue you'll see what was once a massive pipe that went from an old dam, down toward Mackay.  The pipe was made from metal coils with wood planks tarred to the inside. Portions of this metal coil are everywhere including where the trail is, and in the stream bed. The diameter of the pipe is about 3 feet and it extends for 3 miles, so you can imagine how much material is left around. At around 2 miles you'll pass an impressive waterfall coming in from the northwest slopes of Wet Peak.  After passing the historic dam that was breached, the trail becomes faint and you'll need to scramble through the wooded forests on the sides of the drainage to avoid rock hopping the creek bed. Once the trees disappear at around 8800 feet, the slope gets dramatically steeper as you approach a series of limestone cliffs that are easily circumnavigated.  Some of these cliffs may have water seeping down them giving them the appearance of "weeping walls".  The tarn lake at 9870 is a prominent landmark, as is the dramatic twin towers above this area.  Follow the slope north contouring an obvious drainage line until your on the southwest ridge proper. Follow this to below the uppermost limestone band and carefully traverse an exposed ledge of loose rock and/or snow over a giant drop-off on the northwest side.  The true summit is just north of this crux. Notice a natural limestone arch underneath the south summit- look through it to view the peaks to the south!

Conditions and Season

Standard climbing season is April through November  Conditions may vary greatly.  There are periods of very dry and cold weather in the winter. 

Nearby Mackay, Idaho Climate Data:

Jan Feb  Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Average Max. Temperature (F)  29.2 34.2  43.0 55.2 65.2 74.1 84.1  82.7 73.3 60.1 42.1  31.3 56.2
Average Min. Temperature (F) 5.6  10.1 18.9 28.1 35.9  42.3  48.4 46.3  38.3  30.0 18.7  8.9 27.6
Average Total Precipitation (in.) 0.78 0.61 0.61 0.68 1.09 1.34 0.93  0.80 0.67 0.57  0.59   0.78  9.43
Average Total SnowFall (in.) 7.5 5.9  2.4 0.5 0.1  0.0  0.0  0.0 0.1  0.2  2.0  7.3  26.1
Average Snow Depth (in.)  4 1 0  0 0 0 0  3  1

For general comparison, the Lost River Valley is much drier (climatologically a desert) in the winter than some of the ranges to the west in Idaho.  Yet in the summer, the Lost River Valley receives more precipitation.  Periods of dry, cold, and windy weather may lend itself for opportunities to climb nearly year round.



Salmon-Challis National Forest Info

National Weather Service Current Forecast for Mackay:

LOwer Cedar Creek Cliffs



Children refers to the set of objects that logically fall under a given object. For example, the Aconcagua mountain page is a child of the 'Aconcagua Group' and the 'Seven Summits.' The Aconcagua mountain itself has many routes, photos, and trip reports as children.