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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 Distance5 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

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

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The turnoff is easy to miss; the campground is not visible from the road.
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There’s a sign across the road from the entrance.
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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.
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The parking lot is a decent size. Get here early to secure a spot.
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You need a parks pass or Adventure pass to park at the trailhead.
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There are primitive toilets at the trailhead.
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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.

Altra Lone Peak

The Most Comfortable Hiking Shoe Ever
For most people, the Altra Lone Peak 4.5 (Women: REI | Amazon  + Men: REI | Amazonis 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 work great on the trail. It’s a favorite of PCT and AT hikers for a good reason!

Garmin Inreach Mini Beacon

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.

Gaiagps

Gaia GPS Mapping App
Smartphones are not backcountry instruments, but almost everyone has one today. And they all have GPS onboard. So I recommend getting a good GPS hiking app like Gaia GPS that supports offline maps. Just make sure to put your phone in airplane mode so the battery doesn’t drain. GaiaGPS not only has smartphone and tablet apps, but also an online planning tool. You can drag the GPX hike tracks from my (or any) guides into the online map and they will sync to your phone. You can also check for wildfires, weather, snow, and choose from dozens of map types with a premium membership (HikingGuy readers get up to 40% off here). Note that I also carry a paper map with me in case the phone dies or gets smashed.

Here’s my complete gear list that I personally use, have tested, and recommend, updated February 2021.

My February 2021 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 offset website expenses. 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 Map

Download the Hike GPX FileView a Printable PDF Hike Map

Fenix 6 Pro

How are you going to navigate this hike?
To start, you should always have a paper map and compass. And it helps to print this guide out or save it on your phone. I highly recommend a GPS as well. I use the Garmin Fenix 6 Smart GPS watch ( REI | Amazon | My Review) with maps (or the more affordable Garmin Instinct). The GPS smartwatch is nice because it’s rugged, works if your phone dies, and also has a billion other features like sleep tracking, workout recording, etc.

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

Watch This Video In 360/VR Why 360/VR Is Great

Turn by Turn Directions

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Look for the fenced start of the hike.
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Once the fence ends, go left and then up the hill. To the right are picnic tables.
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There are no trail markings, but the path is well worn and generally easy to follow.
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The trail crosses a few ravines as it winds up through the forest.
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Go straight through at the utility poles.
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There are several benches along the trail.
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You’ll start to get some glimpses through the trees.
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And about 0.5 miles in, you’ll arrive at this viewing platform.
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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.
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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.
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The trail makes its way through some more heavily vegetated sections.
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You’ll cross a small bridge over an unnamed drainage.
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When you come to the bench, hike to the right and down the hill.
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And after that, you’ll see a fence. The trail continues to the right of the fence.
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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.
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And at a clearing you’ll see the road over to your left, across the field.
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Now there’s a bit more climbing. Head up the mini-switchbacks.
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And then downhill for a short stretch.
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At the bench, keep to the right.
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Hike past another private property sign.
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And soon you’ll come to the end of the Observatory Trail.
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There’s this funky old sign at the trailhead here.
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Hop onto the road and take the left entrance to visit the Palomar Observatory if it’s open.
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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 February 19, 2021. Did something change on this hike? If so, please contact me and let me know. I'll update the guide.

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