Palomar Mountain Observatory Trail

In This Guide	Video and Turn by Turn Observatory Trail Directions How to Get to the Palomar Mountain Observatory Trail Tips and Recommendations for the Hike
Total Distance	5 miles (8.1 km)
Hike Time	2-3 Hours (Total)
Difficulty (?)	Moderate
Total Ascent (?)	1,000 feet (305m)
Highest Elevation	5,617 feet (1712m)
Fees & Permits	Parking Permit
Dogs Allowed	Leashed
Alerts & Closures (?)	Cleveland National Forest
Park Phone	858-673-6180

The Palomar Mountain Observatory Trail is a gentle hike that offers a lot of scenery packed into a short distance. One of the only National Recreational Trails in San Diego, the hike takes you through mountain pines and cedars, offers panoramic viewpoints, and ends at the iconic Palomar Observatory, the largest in the world from 1948 to 1976. The Observatory Trail is easy to follow, not too steep, and great for families.

Where Is the Palomar Mountain Observatory Trail?

The Observatory Trail starts, appropriately enough, at the Observatory Campground, about 2 miles down the road from Palomar Observatory. The campground is popular with stargazers; several tent sites have open areas for viewing the night sky. And several times each year amateur astronomers come here for star parties. Within the campground is a day-use parking area for the Observatory Trail.

Use this address:
Observatory Campground, Co Hwy S6, State Park Rd #21485, Palomar Mountain, CA 92060

Palomar Mountain Observatory Trail 1 — The turnoff is easy to miss; the campground is not visible from the road.

Palomar Mountain Observatory Trail 2 — There’s a sign across the road from the entrance.

Palomar Mountain Observatory Trail 3 — Head down the hill to the campground.

Observatory Trail Parking — Once you’re on the campground road, bear right to drive around the loop to the day use parking.

Palomar Mountain Observatory Trail 4 — The parking lot is a decent size. Get here early to secure a spot.

Palomar Mountain Observatory Trail 8 — You need a parks pass or Adventure pass to park at the trailhead.

Palomar Mountain Observatory Trail 6 — There are primitive toilets at the trailhead.

Palomar Mountain Observatory Trail 5 — And there’s a handy water spigot to fill your bottles.

Gear For the Hike

This isn’t a particularly challenging hike from a technical standpoint, so nothing special is really needed. If you have light hiking gear and hiking footwear, that’s your best move. Otherwise fitness clothes will work well. Take at least 1L of water for the trip. In the summer, bugs can be a pain; bring insect repellant. And as you’ll see in my pictures, it does occasionally snow here. Prepare for it to be about 10F cooler up on the mountain than down in the valley (as a rule of thumb). There are older trail reports of overgrown poison oak and poodle dog bush along the trail, but in recent years the Forest Service (specifically the volunteer who lives at the Observatory Campground) has done a great job of keeping the trail clear.

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Best All-Around Day Pack: Osprey Talon
I try so many backpacks and I can usually find something I love about all of them. But no matter how many I try, I always find that I come back to the Osprey Talon 33 (or for women, the Osprey Sirrus 36). It’s just the right balance between everything. You save weight because there is no frame, but the vented and padded back holds its shape, giving it a pseudo-frame. It’s big enough for long day hikes or overnighters, but when I don’t fill it on a shorter hike, it’s still nice and light. It’s got a sleeve for a hydration bladder and side pockets for Smartwater bottles. I’ve been using (and beating) the same one since 2017 and it’s still going strong.
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Stay Safe Out of Cell Phone Range
If you’re not familiar with the Garmin InReach technology, it allows you to send and receive text messages where you don’t have cell phone signals. You can also get weather reports and trigger an SOS to emergency responders. Even if you don’t have an emergency, sending a quick message telling a loved one that you’re okay or are running late is well worth the cost. The Garmin InReach Mini (REI | Amazon | My Review) fits in your palm and weighs next to nothing.

Here’s my complete gear list that I personally use, have tested, and recommend, updated December 2020.

My December 2020 Top Gear Picks

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Observatory Trail Maps

Even though the hike is in a not-so-busy hiking area, the trail is generally in good condition and well maintained. If you look at a map, you’ll see that the Observatory Trail roughly follows the road that goes to the observatory. For the majority of the hike, you never see the road. But during summer weekends when the road is busy, you can hear traffic noise.

Download the Hike GPX File View a Printable PDF Hike Map

Elevation Profile

The hike to the observatory is a climb, but it’s not too hard. Any steep sections are pretty short.

3D Map

Hike Brief

Palomoar Observatory Stamp — When the Observatory opened in 1948, it was “kind of a big deal” in the parlance of San Diego’s Anchorman. The observatory’s Hale Telescope was the largest in the world until 1976 when the Russians finally caught up and built a bigger one.

The observatory is owned and operated by the California Institute of Technology (Caltech). You can visit the telescope and small museum if they’re open. Check the website for hours and information.
George Ellery Hale, who oversaw construction of the observatory at Mt Wilson, got funding to build this observatory in 1928. By that time light pollution from a growing LA was making the Mt Wilson Observatory less effective.
The 200 inch Hale Telescope is made out of Pyrex glass, the same you can find in almost everyone’s kitchen.
Edwin Hubble (of which the Hubble Space Telescope was named after) was the first astronomer to use the Hale Telescope. The observatory was responsible for many discoveries, including quasars.
Why is it called Palomar Mountain?
- The native Luiseños people called it Wavamai.
- When the Spanish arrived in 1798 they named the valley “cañada de palomar” which means “valley of the pigeon roost” after the numerous band-tailed pigeons living here. Although the band-tailed pigeon population is on the decline, you can still spot them here at Palomar, which is one of the only places in the American west where they live.
  The band-tailed pigeon is the largest in North America. Unlike the city variety, the band-tailed pigeon is shy and tough to spot. Look for them foraging on the ground for acorns, or more likely up on the trees, where they often hang upside down like a parrot. When they take off their wings make a loud sound. Photo Peter Wallack
- At one time it was named Smith Mountain, after a sea captain who settled here and was later murdered here. There’s a whole story involving Smith, his fellow settler on the mountain, a freed slave named Harrison, and a British ship deserter turned murder It’s an interesting read in this San Diego Reader article which also covers some history of the area.
- Locals didn’t like the name Smith Mountain and changed it back to Palomar in 1901. It all became official when the Palomar Mountain Post Office opened in 1920 (next to the General Store that you pass on the way to the hike).
The Observatory Trail is one of the only hiking trails on Palomar Mountain. Much of the land in the area is owned by cattle ranchers or the observatory. Palomar Mountain State Park, to the west of here, doesn’t actually encompass the peak of Palomar Mountain.
This is a great hike for fall colors, which usually hit around November.

Laguna Mountain Skipper — The Observatory Trail goes through the habitat of the very rare and endangered Laguna Mountains Skipper butterfly. They’re the size of a quarter and look like a moth. Your best chances to spot them are in May and July. Photo iNaturalist

Palomar Mountain Observatory Trail Hike Directions

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Hike Video

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Turn by Turn Directions

Palomar Mountain Observatory Trail 7 — Look for the fenced start of the hike.

Palomar Mountain Observatory Trail 9 — Once the fence ends, go left and then up the hill. To the right are picnic tables.

Palomar Mountain Observatory Trail 10 — There are no trail markings, but the path is well worn and generally easy to follow.

Palomar Mountain Observatory Trail 11 — The trail crosses a few ravines as it winds up through the forest.

Palomar Mountain Observatory Trail 12 — Go straight through at the utility poles.

Palomar Mountain Observatory Trail 13 — There are several benches along the trail.

Palomar Mountain Observatory Trail 14 — You’ll start to get some glimpses through the trees.

Palomar Mountain Observatory Trail 15 — And about 0.5 miles in, you’ll arrive at this viewing platform.

Palomar Mountain Observatory Trail 16 — From here you get a perfect view down the Mendenhall Valley, named after Enos Mendenhall, a cattle rancher who settled here in the 1860s. In the distance is Whale Peak, located in Anza-Borrego State Park.

Palomar Mountain Observatory Trail 17 — Right after the platform you’ll get a glimpse of the Observatory, the only place you’ll see it before you get to the top.

Palomar Mountain Observatory Trail 18 — The trail makes its way through some more heavily vegetated sections.

Palomar Mountain Observatory Trail 19 — You’ll cross a small bridge over an unnamed drainage.

Palomar Mountain Observatory Trail 20 — When you come to the bench, hike to the right and down the hill.

Palomar Mountain Observatory Trail 21 — And after that, you’ll see a fence. The trail continues to the right of the fence.

Palomar Mountain Observatory Trail 22 — You’ll see a private property sign. From here you are leaving Cleveland National Forest. As long as you stay on the trail, it’s all legal.

Palomar Mountain Observatory Trail 23 — And at a clearing you’ll see the road over to your left, across the field.

Palomar Mountain Observatory Trail 24 — Now there’s a bit more climbing. Head up the mini-switchbacks.

Palomar Mountain Observatory Trail 25 — And then downhill for a short stretch.

Palomar Mountain Observatory Trail 26 — At the bench, keep to the right.

Palomar Mountain Observatory Trail 27 — Hike past another private property sign.

Palomar Mountain Observatory Trail 28 — And soon you’ll come to the end of the Observatory Trail.

Palomar Mountain Observatory Trail 29 — There’s this funky old sign at the trailhead here.

Palomar Mountain Observatory Trail 30 — Hop onto the road and take the left entrance to visit the Palomar Observatory if it’s open.

Palomar Mountain Observatory Trail 31 — Walk down the paved road.

Palomar Observatory Map — Here’s a layout of the Palomar Observatory. Just go straight through to see the Hale Telescope. Photo Palomar Observatory

Palomar Visitor Center — You can stop at the Greenway Visitor Center if it’s open. Photo Wikimedia

Palomar Hale — And finally you’ll reach the Hale Telescope dome. If it’s open you can go inside and check it out. Photo Bill Dickinson

Once you’ve had your fill at the observatory, just turn around and go back the way you came. You can also hike back down on the road if you’d like, just watch out for cars, there is no sidewalk.

Cover photo by Sebastian Wallroth

Did something change on this hike? If so, please contact me and let me know. I'll update the guide.