Mount Heinen

Elevation: 6,336 ft
Prominence: 1,516

This Grand Slam peak is not in the book. There are four routes listed below in order of popularity. All four routes involve steep Class 2 hiking. Updated June 2019


Mount Heinen is located in the Boise Mountains, in the Boise National Forest, about 4 miles north-northwest of Arrowrock Reservoir. This peak is one of the four peaks of the Grand Slam Peaks, the other three peaks are Kepros MountainCervidae Peak, and Shaw Mountain.

Mount Heinen is the tallest of the Grand Slam Peaks. It is a great early season hike, but it is a strenuous climb from any direction. There are four routes outlined below. The standard route, the North Face Route, the Southwest Ridges Route and the Orth / Koehler route.

USGS Topos: Dunnigan Creek, Arrowrock Reservoir NE, Grape Mountain

Access

Access begins at the point where FS-327, [(C) page 154] The Middle Fork Boise River Road leaves ID-21. This junction is 6.1 miles north of the the Lucky Peak dam. The junction is signed for Atlanta, Idaho. Follow this paved road along Lucky Peak Reservoir to Arrowrock Dam. The pavement ends just short of the dam. Set your odometer to zero at the top of the dam.

0.0 Arrowrock Dam. The road along Arrowrock Reservoir is narrow, washboard gravel with many blind turns and significant dangerous drop-offs. On weekends traffic can be high, Drive slow and responsibly.

0.7. Unnamed drainage. The Trailhead for Southwest Ridges Route.

1.4. Cinch Creek. Second Trailhead for Southwest Ridges Route.

7.5. Irish Creek Boat Ramp and the Standard Route trailhead.

9.0: Cottonwood Creek Road, FS-377 Junction. Turn left. This road’s condition varies from year to year. In 2019 it was in good condition with only a few rough spots. High Clearance recommended.

9.9: Cottonwood Guard Station.

15.0 Cottonwood Creek/South Fork Thorn Creek Pass, elevation 4,848. Park here for the North Face Route.


Standard Route: Southeast Ridge (Class 2)

The route starts on the northwest side of Arrowrock Reservoir. Park just north of the Irish Creek Boat Ramp. This route was originally a motorcycle track but is now designated for foot traffic only. The track  can be viewed from this spot as it climbs up the steep slopes to the west. Follow this track upwards and to the northeast toward Point 5402.

The trail climbing steeply up the slopes above Irish Creek.

The trail climbing steeply up the slopes above Irish Creek.

The route now follows an overgrown fire break until just south of Point 6137. Traverse around Point 6137 and then continue north along the ridge that leads to Mount Heinen. This is a long, strenuous route. Take lots of water. Since I first climbed this route in 2000 a use trail has been beat in for nearly the entire distance. The route is roughly 10.0 miles with 3,500 feet of gain round trip.

The USGS maps covering the route are Dunnigan Creek, Arrowrock Reservoir NE, Grape Mountain

The standard, southeast ridge route to Mount Heinen.

Approaching Point 5402.

Approaching Point 5402.

heinen 2

View of the summit from near the top of Point 5402.

View looking toward the summit from the low point between Point 5402 and the summit.

View looking toward the summit from the low point between
Point 5402 and the summit.

heinen 4

Looking back down the ridge.


North Face Route (Class 2)

This route is a little shorter, 9.2 miles, than the Standard Route and has much less elevation to gain with only 1,625 for the climb and 264 feet on the return. Nevertheless, it still includes a steep, difficult 900 foot section up the north face.

This route leaves FS-377 at the top of the North Fork Cottonwood Creek/South Fork Thorn Creek Pass. The route utilizes the FS-202 road system, a group of closed logging roads. The road is not well mapped on either the Forest Service or USGS maps as it includes a number of roads not shown on the maps. FS-202 and 202C are in good shape though 202C has brush encroaching on the tread in places. Unfortunately, none of the roads have signs designating which road is which. While I have hiked this route I highly recommend using a mountain bike for the first 3.6 miles.

Heinen viewed from FS-202C.

Heinen viewed from FS-202C.

Follow FS-202 west from the pass past the gate for 0.4 miles to a junction. Go left. The road now winds in and out of drainages to the ridge top where it turns south. Roughly 1.9 miles from the pass there is a Y-junction keep right and you will immediately come to a second Y-junction. This junction is the beginning of FS-202C. Go left.

This Google Maps photo show the confusing intersection. You want FS-202C.

This Google Maps photo show the confusing intersections at 1.9 miles. You want FS-202C.

FS-202C quickly wiggles its way steeply up the ridge, staying on the east side at first and then crossing to the west side between Point 5710 and Peak 5740. Once past Peak 5740 the road stays on the ridge top until it reaches Point 5645 at 3.6 miles. From this point the road drops into the saddle below Heinen’s north face losing 200 feet. While this section is rideable, I leave my mountain bike at Point 5645.

From the saddle, 5,444 feet, the trail steeply climbs to the peak’s lower eastern summit. This section of trail appears to be an old fire break which is occasionally traversed by elk and the occasional human. The trail is brushy in spots and always steep as it climbs up the face. As shown on my GPS track it is possible to leave the trail short of summit ridge and traverse directly to the summit. Round trip is 9.2 miles with 1,900 feet of gain.

My GPS tracMy GPS track for the North Face Route.

My GPS track for the North Face Route.

The ridge top road is good enough for mountain biking. I have never been on this road when the gate was open.

The ridge top road is good enough for mountain biking. I have never been on this road when the gate was open.

The steep trail leading up the north face.

The steep trail leading up the north face.

Whether you are walking or riding a bike, the north ridge is delightful in late Spring and early Summer.

Whether you are walking or riding a bike, the north ridge is delightful in late Spring and early Summer.


Southwest Ridges Route, Class 2

This route (or routes) is the longest route discussed on this page but it has two advantages over the other routes. The first advantage is that it starts near the Arrowrock Dam and thus, the driving approach is much shorter. The second advantage is that it is less steep than the other routes.

There are two ridges that run on either side of Cinch Creek that climb more gradually than the Standard Route up to Heinen’s south ridge. John Platt suggested the route and along with Dan Robbins and four others we climbed up the ridge on the west side of Cinch Creek and descended the ridge on the east side. This was in 2007 and none of us were carrying a GPS. I estimate the distance at 12.0 miles with 3,500 feet of gain round trip. See John’s trip report which is linked below.

Access

There are two parking options as shown on John’s map below. After Passing the Arrowrock Dam you can park at the first intermittent flowing drainage you encounter or you can proceed on to Cinch Creek which is the a major drainage that is difficult to miss. See the map below.

Route

Both ridges are classic ridge walks with good game trails for much of the distance. The ridge on the east side of Cinch Creek is the shorter route at around ten miles. If you climb the ridge on the west side you will encounter a thick forest in the saddle between Point 6060 and Heinen’s south ridge. This area will hold snow longer than most points along the route. Whichever ridge you climb your goal is to link up with Heinen’s south ridge on the north side of Point 6137. From there, follow the Standard Route to the summit.

John Platt’s route map. We ascended the ridge west of Cinch Creek and descended the ridge on the east side.

John Platt’s route map. We ascended the ridge west of Cinch Creek and descended the ridge on the east side.

This view is typical of the terrain found on both ridges. Note the game trail and the elk. John Platt Photo

This view is typical of the terrain found on both ridges. Note the game trail and the elk. John Platt Photo


Orth / Koehler Route (Class 2)

Brian Orth, Toni Orth, and Abe Koehler hiked this alternative approach to the summit.

Brian describes the climb as follows: “We were also going to go up Garden Gulch, but it has a no trespassing sign at the bottom of it, so we headed up the wrong ridge on Wood Gulch instead. We figured the route out on the way down.”

Orth / Koehler route.

Orth / Koehler route.

Approaching the north side of Heinen.

Approaching the north side of Heinen.

Climbing up the steep north side of the peak.

Climbing up the steep north side of the peak.

 

Mountain Range: Boise Mountains

Year Climbed: 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 X2, 2008, 2009, 2010, 2013, 2014, 2019

Longitude: -115.87611   Latitude: 43.6616

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