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Palomar Mountain Observatory Trail

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 Time2-3 Hours (Total)
Difficulty (?)Moderate
Total Ascent (?)1,000 feet (305m)
Highest Elevation5,617 feet (1712m)
Fees & PermitsParking Permit
Dogs AllowedLeashed
Alerts & Closures (?)Cleveland National Forest
Park Phone858-673-6180
Weather & ForecastLatest Conditions
Stay SafeCopy this webpage link to the clipobard and share with a friend before you hike. Let them know when to expect you back.

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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Garmin Inreach Mini 2

Garmin InReach Mini 2
I’m a firm believer in carrying a satellite communications device which works where cell phones don’t. I use a Garmin InReach which lets me send text messages back and forth to my family to let them know that I’m okay or if my plans change when I’m out in the backcountry. It also has an SOS subscription built-in so that you can reach first-responders in an emergency. The devices also offer weather reports, GPS, and navigation functionality (what’s the difference between a GPS and satellite communicator?). For a few hundred bucks they could save your life, so for me it’s a no brainer to have something like a Garmin InReach. If you use a smartphone to navigate and want a more affordable option that integrates with your phone easily, check out the ZOLEO.

Latest Prices: Amazon | REI

Lone Peak 6 Yellow

Altra Lone Peak 6
For most people, the Altra Lone Peak is a solid choice that will leave your feet feeling great at the end of any hike. The feel is cushy and light, and if it had a car equivalent, this would be a Cadillac or Mercedes Sedan. The grip is great and they’re reasonably durable for this type of trail runner, which I think is better in most conditions than a hiking boot, and here’s why. The downside of this shoe is that it won’t last as long as something like the Terraventure 3 or Moab 2 (see alternate footwear choices at the bottom of my gear page). I’ve been using mine for many miles and my feet always feel great. I have a video on the details of the Altra Lone Peak 6 here.

Women’s Latest Prices: REI | Amazon 
Men’s Latest Prices: REI | Amazon 

Black Diamond Ergo Poles 2

Black Diamond Trail Ergo Cork Trekking Poles
I’ve gone back and forth on trekking poles, but I think for most people they are a good investment. They help you dig in on the uphills, provide stability on loose downhills, act as a brace when crossing streams, and can probably poke away aggressive wildlife in a pinch. The Trail Ergo Cork poles are a good balance of light weight, durability, affordability, and ease of use. If you want something ultralight and a little more pricey, I’ve had great luck with the Black Diamond Z Poles too.

Trail Ergo Poles: REI | Amazon 
Z-Poles: REI | Amazon 

Gregory Zulu 30

Gregory Zulu 30 & Jade 28
After testing quite a few backpacks, the Gregory Zulu 30 (and Jade 28 for women) is, for most hikers, the best all-season day-pack. First off, it’s very comfortable, and the mesh “trampoline” back keeps your back dry. Its 30L capacity is enough for all the essentials and plenty of layers for winter hiking. External pockets make it easy to grab gear. It’s hard to find something wrong with the pack; if anything, it could be a bit lighter, but overall, it’s not heavy. And its price-point makes it not only affordable but generally a great value.

Women’s Latest Prices: REIAmazon 
Men’s Latest Prices: REIAmazon 

Here’s my complete gear list that I personally use, have tested, and recommend, updated June 2022.

My June 2022 Top Gear Picks

No company pays me to promote or push a product, all the gear you see here is gear I use and recommend. If you click an a link and buy gear, I get a small commission that helps keep the website ad and promotion free. There is no cost to you.

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.

Click Here To View

Explore Map on CalTopoView a Printable PDF Hike MapDownload the Hike GPX File

If you try to download the GPX file and your browser adds a “.txt” or “.xml” extension to it, simply rename it as a “.gpx” file.


How Are You Going to Navigate This Hike?
Here’s what I use. If you are a hardcore hiker and/or hike in extreme conditions, I recommend getting a dedicated GPS like a GPSMAP 66sr or 66i, or a wrist-based GPS with maps like the Garmin Fenix 7 or Epix. If you only hike in fair weather and a touchscreen is fine, or just want a solid tool, I highly recommend downloading the smartphone app, Gaia GPS. It’s a piece of cake to use and very powerful, just make sure your phone is in airplane mode so the battery doesn’t drain. You can also check for wildfires, weather, snow, and choose from dozens of map types with a premium membership (HikingGuy readers get a big discount here). Note that I also carry a paper map with me in case the phone dies or gets smashed.

To access this guide when out of cell phone range on the trail, simply save the webpage on your phone ( iPhoneAndroid ).

Elevation Profile

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

3D Map

Observatory Trail Elevation 3d Map
The trail roughly follows along the S6 / South Grade Road as it makes its way uphill.

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.
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

This guide last updated on May 18, 2022. Did something change on this hike? If so, please contact me and let me know. I'll update the guide.

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