Benchmark Mountain (indicated on some maps as Bench Mark Mountain) is the high point on West Cady Ridge, 20 miles northeast of the town of Skykomish, WA. Benchmark was named in 1896 by government surveyors who places a benchmark on the summit. The historic benchmark is either no longer there or difficult to find and not on the actual high point. It's likely to have been stolen since the summit area is composed of dirt and loose rock. The mountain was once the site of a fire lookout and there are still some suggestive remains to that end, just north of the summit.
The main approach for Benchmark Mountain is the West Cady Ridge trail which begins in the Wild Sky Wilderness and crosses over into the Henry M. Jackson Wilderness. There is a trail all the way to the summit and it follows the ridge crest most of the way. Several books have the round trip distance listed as 16 miles but in reality, it is closer to 14 miles. With approximately half the trail leading through alpine meadows, this peak is famous for it's flowers and huckleberries.
Beginning at the West Cady Ridge trail head, a bridge crosses the North Fork Skykomish River in the first tenth mile. During spring and summer melt-off, this tributary is a raging torrent which has cut a deep gouge into the existing bedrock. Beyond the bridge the trail climbs steadily in a meandering southern direction. There are many switchback but the grade is so well constructed that it doesn't actually feel like 2000 feet of gain to the ridge top.
Once on the ridge top, the trees will thin out and views of the local monsters like Sloan Peak and Kyes Peak begin creeping up behind you. Follow the trail east by southeast until you reach 5100 feet at which point the trail starts curving more and more to the north finally reaching the summit at 5816 feet. There are several high point along the ridge which don't look like much on the map but actually add a considerable amount of up and down.
Take US Highway 2 just to just west of milepost 50. Turn north onto Forest Service road #65 which should be indicted with a sign that says "Beckler River Road". Follow this road for 14.4 miles as it runs parallel to Beckler River and then rises up and over Jack's Pass. After the first 7 miles the pavement will end but usually the road is well maintained.
On the far side of the pass it will drop down and cross over the North Fork Skykomish river. Shortly after crossing the river, 14.4 miles from Highway 2, turn right onto Forest Service road #63. Following this for another 4.2 miles to the end where you will find three trail heads. The West Cady Ridge trail begins on the south side of the parking lot. There is an outdoor pit toilet near the parking lot, that is if it's not buried under snow.
Check Road Conditions
A Loop Option
Want to bag 5 peaks in 2 days? Have I got the trek for you!
There is a loop option which begins on the West Cady Ridge trail and ends on the Quartz Creek trail leading directly back to the same parking area. This trek is 23.5 miles and with less than 5000 feet of vertical gain on good quality trail, it is easily done in 2 days. Just picture it: Benchmark Mountain, Skykomish Peak, June Mountain, Long John Mountain, and Bald Eagle Mountain.
Follow the above directions to the summit of Benchmark Mountain and then descend 250 feet back to the West Cady Ridge trail and continue to follow it east to it's official end where it makes junction with the Pacific Crest Trail. Follow the PCT north to Cady Pass being careful to avoid the fork which leads down into the Pass Creek Basin. After a climb of Skykomish Peak, continue north past Lake Sally Ann and Wards Pass to Dishpan Gap. At this four way junction, exit the PCT and continue northwest, once again being careful to avoid a wrong turn which would descend into the drainage.
Turn left at the next fork and continue west to June Mountain. Next along the ridge will be Long John Mountain and Bald Eagle Mountain before finally descending northwest to Curry Gap. From Curry Gap, turn south and follow the Quartz Creek trail all the way to your car. Be sure to carry a lot of water in the summer as the ridge tops become very dry. There are only a few lakes along the way where you could use a filter.
David has posted a good photo trip report about the loop.