In the mountainous area north of the Cooke City area (okay, that was a little dumb-- it is mountainous in all directions from Cooke City), the Absarokas and the Beartooths converge, and the task of properly assigning the peaks to their parent ranges becomes challenging. No passes or rivers serve as textbook dividers. The peaks in this no-range's land do not consist of the very different rock types that characterize the two ranges.
Henderson Mountain lies in this hinterland. And it is a Beartooth Peak because...
...the few sources on this that I have found place Henderson among the Beartooths. These sources seem to suggest that the magic line south of the Boulder River, which divides the Montana Absarokas (by some called the Western Beartooths) from the Beartooths, follows the Stillwater River to either Bull of the Woods Pass or Daisy Pass and then along Miller Creek to U.S. 212.
Since Henderson is east of this magic line, it is a Beartooth peak. And for those concerned with such things-- it is a ranked peak.
Henderson is close enough to unpaved roads to make it a pretty fast and easy climb but far enough from paved ones to yield views that have a strong wilderness feel and which actually do stretch into some of the Lower 48's wildest terrain.
Another great thing Henderson has going for it is the fact that it houses Chimney Rock, an easily seen feature just off the crest of its NW ridge. Chimney Rock is a pillar that presents a Class 5 challenge to reach its top. It's only about 25-30' of climbing, but it's worth doing (more info farther down).
Index, Pilot, and Henderson
My Friend the Fox
The fastest and easiest way to the summit is from Daisy Pass, though that is not how I went. To find the turnoff, drive east of Cooke City a short distance and then turn north onto a road signed for Daisy Pass and/or Bull of the Woods Pass. The road to Daisy Pass is marked as an improved unpaved road. Beyond Daisy Pass, the road is marked as 4wd.
The way I went was via Lulu Pass after climbing Fisher Mountain
. Shortly east of Cooke City, east of the previously mentioned turnoff, turn north onto a road signed for Lulu Pass. Drive nearly 3 miles to the intersection of the road to Lulu Pass (left) and the road to Goose Lake (right). There is some room to park here if you have low clearance and want to walk the remaining 3 miles to Lulu Pass. However, I was able to drive a Subaru Legacy to within half a mile of the pass.
Henderson Mountain, dawn, from the road to Lulu Pass
From Daisy Pass, head E/NE up the slopes and then follow the ridge to the summit. Distance is maybe 0.75 mi, with about 600' of elevation gain. Class 2.
From Lulu Pass, there are two options. Hike the 4wd road to Daisy Pass, or head up the slopes of Fisher and then traverse. If you go via Fisher, it's about 2 miles. Overall elevation gain is about 1000'. Class 2.
Henderson Mountain Summit
View to Index and Pilot
Henderson and Chimney Rock
This obvious feature just off the northwestern edge of the summit ridge offers a "technical scramble" or a short roped climb, though rock quality for pro may be somewhat sketchy.
There are a number of lines one could try. I found a way that felt, say, 5.2-5.4.
My guess is that most people who climb this feature just free solo it as I did, unless they climb a harder line and downclimb the one I used. There were no fixed anchors up top, and no slings/webbing from past rappels.
When to Climb
Summer and early fall.
As this area is popular with snowmobile operators, winter ascents are possible as well.
There are some campgrounds off U.S. 212 near Cooke City. However, dispersed camping is widely available along the roads to Lulu Pass and Daisy Pass, and it is free. Watch out for the grizzlies, though.