The Union Hill Trail Area is part of the 800-acre Empire Mine State Historic Park. The trails in this area are enjoyable for hiking, jogging, bicycling, and horseback riding. Separated by the Colfax Highway 174 from the main part of the park that contains the visitor center, historic buildings, and mining machinery, the Union Hill Trails Area has fewer visitors. It is a beautiful, peaceful place to enjoy nature that is only a short distance from Grass Valley. Union Hill contains a network of trails that allows visitors to plan loop hikes of varying lengths.
Place: Grass Valley, CA
Season: Year around
Land: Empire Mine State Historic Park
Trail signs: Good direction signs throughout trail the network
Length: Longest continuous distance is a 2.9 mile loop following various trails around the periphery of the Union Hill Trails Area.
Altitude change: Depends on the trail taken. Maximum net elevation change about 175 feet.
Trail surface: Native soil
Environment: Heavily wooded with a wide variety of trees, shrubs, and seasonal wildflowers. Trees include ponderosa and sugar pine, Douglas fir, incense cedar, oak and maple.
Rules: Park trails are open from dawn to dusk; stay on marked trails; no motor vehicles; no camping; dogs must be on leash; all natural and historic features of the park are protected. Caution: poison oak, ticks, and rattlesnakes.
Gold Hill Trailhead: The primary trailhead is adjacent to a parking area at the end of Gold Hill Drive. (N39.21152 W121.04351) From Grass Valley, take the Colfax Highway 174 approximately 1.1 miles southeast from Highway 49 to Silver Way. Turn left onto Silver Way and take the second right turn onto Gold Hill Drive and follow it two blocks to the parking area by the trailhead.
Colfax Highway Trailhead: A secondary trailhead is located along the Colfax Highway 174. (N39.20719 W121.04144) From Grass Valley, take the Colfax Highway 174 approximately 1.5 miles east from Highway 49 and look for horse crossing signs along both sides of the highway just before you see the Calvary Bible Church on your right. The trailhead is visible as a wide dirt path next to the horse crossing sign on the north side of the highway. It is about 100 yards west of Mark Drive. There is no parking at the trailhead, but you can find road shoulder parking nearby. Please park completely off the road and take care crossing the busy highway.
Trail tips: There are many ways to walk or ride through the Union Hill Trails area, depending on your time and interest. Below are some suggested routes:
Loop Around the Periphery: By following several different trails, you can make the longest possible one way loop of the Union Hill Trail Area. It is a 2.9 mile circuit with less than 200 feet of net elevation gain and loss. It provides an excellent example of the natural features of the area.
Quick Description: This route goes clockwise around the periphery of the entire Union Hill Trail Area. Starting at the Gold Hill trailhead, follow the Upper Union Hill Trail east for its entire length, go clockwise around most of the Indian Ridge Loop Trail to the water tanks intersection, then return to the Gold Hill trailhead via a short section of the Indian Ridge Trail, the Indian Ridge Crosscut Trail and the Lower Union Hill Trail.
Detailed description: Starting at the Gold Hill trailhead, go about 100 feet east and turn left onto the Upper Union Hill Trail. After about 0.4 mile on the Upper Union Hill Trail you will see the Lost Loop Trail taking off to your left. It’s only about 0.2 mile out and back if you want to scout it. Continuing along the Upper Union Hill Trail, you will soon cross a power line right-of-way with large towers and power lines. About 0.2 mile farther on, you will come to the junction of the Pipeline Trail. This junction can be a little confusing. Just be sure to keep left to stay on the Upper Union Hill Trail. It will soon turn toward the south and start going downhill. About 0.3 beyond the Pipeline Trail junction, the Upper Union Hill Trail arrives at the Indian Ridge Loop Trail. Turn left now and follow the Indian Ridge Loop Trail clockwise around its rectangular layout.
The Indian Ridge Loop area has less tree cover than the rest of Union Hill. You will see plenty of open sky up here and some lovely big oaks. As you go around the rectangle (almost exactly one mile), you will walk south along the park’s east boundary line, then west along the back of a residential area, then north and uphill toward two large water tanks near the highest point on Union Hill. At the water tanks junction you will have a rare distant view toward the north along the power line right of way.
From the water tanks junction, go west on Indian Ridge Trail about 0.1 mile to the junction with the Indian Ridge Crosscut Trail. The latter is a shortcut trail that comes up to Indian Ridge from the Colfax Highway 174 trailhead. Take this trail downhill about 0.4 miles to its junction with the Lower Union Hill Trail. (Do not take the side trail you may see on your left after about 0.3 mile.)
When you reach the Lower Union Hill Trail, turn right and follow that trail back to the Gold Hill Trailhead. On the way (<0.1 mile) you will see the Pipeline Trail going up to your right, and after 0.2 mile you will see the Crosscut Trail going up to your right. Shortly after passing the Crosscut Trail junction, the Lower Union Hill Trail bends right and goes uphill a short distance where it meets the Indian Ridge Trail. Turn left and go about 100 feet west, back to the Gold Hill trailhead.
Out Along the Ridge: Another great way to see the Union Hill Trail Area is to walk or ride along its main ridge, then choose one of several options for looping back to the Gold Hill trailhead.
The Indian Ridge Trail is so named because it is an historic trail that was used by the Nisenan group of Maidu Indians. It starts at the Gold Hill trailhead and goes nearly due east and gently uphill 0.6 mile to the water tanks junction where it ends. Along the way you will intersect three trails: the Crosscut Trail on your right at 0.2 mile, the Pipeline Trail crossing at 0.4 mile, and the Indian Ridge Crosscut Trail on your right at 0.5 mile. You can take any of these down to your right. They all end at the Lower Union Hill Trail where you can turn right and return to the Gold Hill trailhead. The mileages of these different loops are: Crosscut Loop 0.6 mile, Pipeline Loop 1 mile, Indian Ridge Crosscut Loop 1.2 miles.
When you reach the water tanks intersection, continue east on what looks like an extension of the Indian Ridge Trail. This is technically a part of the Indian Ridge Loop Trail but you won’t notice much difference. About 120 yards east of the water tanks junction you will find a very nice picnic table in a stand of oaks off to your right. It’s a good place to stop for a while. Continuing east from the picnic table for less than 0.2 mile you will see the Upper Union Hill Trail coming in from the left. From this intersection, three interesting return loops beckon:
(1) Return all the way to the Gold Hill Trailhead on the Upper Union Hill Trail. (Loop total: 1.9 miles)
(2) Return to the Gold Hill Trailhead via the Upper Union Hill Trail, Pipeline Trail and Lower Union Hill Trail. (Loop total: 1.9 miles)
(3) Complete the Indian Ridge Loop Trail clockwise around to the water tanks junction, then follow the Indian Ridge Trail back west to the Gold Hill Trailhead. (Loop total: 2.4 miles)