Millard Canyon's happily splashing stream, presided over by oaks, alders, maples, and bigcone Douglas firs, flows out of the San Gabriel Mountains and down into the urban flatlands of the Los Angeles Basin. The six-mile looping hike into and through this canyon (as described here) reveals plenty of natural beauty, and you can also snoop around the site of the Dawn Mine, a small gold mine worked intermittently from 1895 until the early 1950s.
From Loma Alta Drive in the city of Altadena, drive up the Chaney Trail (a paved road) to the top of Sunset Ridge, where there's parking by the roadside. Walk east on the gated, paved Sunset Ridge fire road. After about 100 yards, pass a foot trail on the left leading down to Millard Campground. Continue another 300 yards to a second foot trail on the left (Sunset Ridge Trail). Take it. On it you contour north and east along Millard Canyon's south wall, passing above the 50-foot-high falls. You begin climbing in earnest at about 0.9 mile and soon reach a trail fork. The left branch (your return route) goes down 100 yards past a private cabin to the canyon bottom. You go right, uphill. Switchbacks long and short take you farther up along the pleasantly shaded canyon wall to an intersection with Sunset Ridge fire road (2.4 miles), just below a rocky knob called Cape of Good Hope.
Turn left on the fire road, and walk past Cape of Good Hope. The trail to Echo Mountain, intersecting on the right, and the fire road ahead are both part of the original Mt. Lowe Railway bed -- now a self-guiding historical trail. Continue your ascent on the fire road/railway bed to post #4 on the left (2.9 miles). There you'll find a trail descending to Dawn Mine in Millard Canyon. This is a reworked but primitive version of the mule path once used to haul ore from the mine to the railway above. On the way down you may encounter a dicey passage or two across perpetually sliding, broken rock.
After reaching the gloomy canyon bottom (3.6 miles), the trail goes upstream along the east bank for about 100 yards to the abandoned Dawn Mine, perched on the west-side slope. The gaping entrance to the lower shaft may seem inviting to explore, but it could collapse without warning.
From the mine, head down-canyon past crystalline mini-pools, the flotsam and jetsam of the mining days, and storm-tossed boulders. Much of the original trail in the canyon has been washed away, but a new generation of hikers has beaten down a pretty good semblance of a path. The bigleaf maples down along the canyon bottom should show their very best autumn color during the next month or so.
After swinging around an abrupt bend to the right, the canyon becomes dark and gloomy once again. After another 0.5 mile you'll come to the aforementioned trail climbing up to the left. Pass the private cabin and hook up with the Sunset Ridge Trail, which will take you back to the Sunset Ridge fire road and your car.