Thunder Spring Loop Featured
play video
Hiking San Diego

Thunder Spring Trail Loop

  • 4.2 miles - Moderate Effort
  • 2 Hours (Total)
  • 900 Total Feet of Climbing
  • Max Elevation of 5,345 feet
  • No Dogs Allowed

The Thunder Spring Trail Loop is one of the quieter hikes in Palomar Mountain State Park; it's a great hike to get away from it all. The scenery is lush, with lots of pines, cedars, and in the spring, wildflowers. You have a climb that will get your heart rate up, but is not too tough. And along the way, you visit a historic homesteader's cabin site. Overall it's a nice trail and a good time.

In this Guide:
  • Video and Turn-by-Turn Directions for the Thunder Spring Trail Hike
  • How to Get to the Thunder Spring Trail
  • Insider Tips and Recommendations for the Hike

Where is the Thunder Spring Trail?

The Thunder Spring Trail hike is located in Palomar Mountain SP. Drive into the park and follow the signs for Doane Pond. There's also a (private) retreat by the pond that might be more GPS-friendly. Use this trailhead address:
Camp Palomar, 34798 Doane Valley Rd, Palomar Mountain, CA 92060

There is an entry fee to enter Palomar Mountain State Park.

Doane Valley French Valley Hike Directions 40
Park at the Doan Pond Day Use Area.
Doane Valley French Valley Hike Directions 41
You won't have to worry about finding parking here, the lot is big. The trail starts on the far side of the parking lot.

Gear For the Hike

The main challenge on this hike can be poison oak and nettles. Wearing long pants solves the problem, just make sure you don't touch your pants if you go through a patch. And there can be gnats, so bring insect repellant. Otherwise this is a straightforward backcountry hike with lots of shade. I bring 1L of water.

Gear That I Love Right Now

Nothing is sponsored or promoted, just the actual gear that I use.

Gear Inreach Mini 2
Garmin InReach Mini 2Hit SOS or just tell loved ones that you're running late where your cell phone has no service.  Review here.
Gear Topo Pursuit
Topo Pursuit 2The best hiking footwear I've ever owned. No blisters. Get them wet, they dry quickly. Lots of cushion and comfort.
Gear Epix Pro Up Ahead
Garmin Epix ProHiking maps, route info, and fitness stats on my wrist. Review here.
Hikelite 26 Gear
Osprey Hikelite 26Lightweight, carries all your gear, and your back doesn't get sweaty. Oh yea, it's also one of the most inexpensive packs you can get.

Check out the complete list here. ( Updated July 2024)

Thunder Spring Trail Maps

Overall the trails are easy to follow and well-marked with signs. You can also save a copy of the handy park handout map which keeps things simple.

Click Here To View

Use This Map:
View in CalTopo | PDF Map | GPX File

Elevation Profile

Thunder Spring Trail Loop Elevation
This profile makes the hike look like a big mountain climb. It's a climb, but only 900 feet total. Once you're at the top, it's almost all downhill back to the start.

3D Map

Thunder Spring Trail 3d Map Elevation
We'll follow the loop clockwise, and climb up along Chimney Creek and Upper Doane Valley. Once we arrive at Chimney Flats, we hike up the ridge, and then back down to the start.

Thunder Spring Trail Hike Directions

Thunder Spring Trail Directions 37
Start at the large trailhead at the end of the parking lot.
Thunder Spring Trail Directions 38
Our next landmark is Thunder Spring.
Thunder Spring Trail Directions 39
You'll pass bathrooms on your right.
Thunder Spring Trail Directions 40
When you get to the junction at the big tree, make the left.
Thunder Spring Trail Directions 41
Stay on the trail that circles Doane Pond, which is a popular fishing spot.

Who is Doane? You can read about him here.

Thunder Spring Trail Directions 42
On the other side of Doane Pond you'll cross a small bridge. Make the hard left once you cross.
Thunder Spring Trail Directions 43
And now you'll see a marker that you are on the Thunder Spring Trail. Hike straight.
Thunder Spring Trail Directions 44
The trail gently climbs in the forest.
Thunder Spring Trail Directions 45
Down to your left is Chimney Creek.
Thunder Spring Trail Directions 46
Hike along the old fence.
Thunder Spring Trail Directions 47
And now you get great views into Upper Doane Valley.
Thunder Spring Trail Directions 48
Here you are, glorious Thunder Spring! Well, it's not so glorious but if you are thirsty, it probably looks a lot more spectacular. Keep hiking straight over the spring.
Thunder Spring Trail Directions 49
You'll pass through the meadow at the top of Upper Doane Valley.
Thunder Spring Trail Directions 50
And then reach an intersection at the top Upper Doane Valley. Continue straight on the Chimney Flats Trail.
Thunder Spring Trail Directions 51
There's a trail marker to confirm that you are on the Chimney Flats Trail.
Thunder Spring Trail Directions 52
Now you start the climbing in earnest. Hike up along the upper reaches of Chimney Creek.
Thunder Spring Trail Directions 53
There's some small switchbacks along the way.
Thunder Spring Trail Directions 54
When the major climbing is over you'll hike along a fence line.

The land on the other side of the fence belongs to a cattle ranch, something you wouldn't expect up on Palomar Mountain. If you drive to the observatory you can see the pastures alongside the road. There has been cattle ranching here since 1860, when the Mendenhall family started bringing cows up to the mountain during the summer (and back down into the valley during the winter). The Mendenhall'ls are still owners of the ranch.

Thunder Spring Trail Directions 55
At about 1.6 miles you'll reach Chimney Flat. Go straight through.
Thunder Spring Trail Directions 56
For the next 0.8 miles or so the trail follows an old shaded dirt road. The road climbs, but it's gradual overall.
Thunder Spring Trail Directions 57
When you reach the top of the climb, you'll come out at some roads. Cross the road and look to the left.
Thunder Spring Trail Directions 58
You'll see the start of a trail just across the road.
Thunder Spring Trail Directions 59
Now you're on the Scott's Cabin Trail. It's mostly downhill from here.
Thunder Spring Trail Directions 60
When you get to the apple orchard, stay straight. The orchard was planted over 100 years ago by the Scott family who owned this land.
Thunder Spring Trail Directions 61
You'll notice that the big trees are gone, replaced by younger pines. This area got hit by the 2007 Poomcha fire, which destroyed 65% of the park.
Thunder Spring Trail Directions 62
Go straight when you see the Silvercrest Picnic Area trail connector on the left.
Thunder Spring Trail Directions 63
And then at about 3 miles in you'll reach Scott's Cabin. On the left is the cleared area where the cabin stood.
Thunder Spring Trail Directions 64
On the right is all the timber that the cabin was built with.

Who was Scott? Most likely it was B. F. Scott, who according to a 1900 census, owned the land here. According to Robert Haley Asher (1868-1953), who lived in the area from 1903-1946, an "ancient log cabin" stood around this area and was often occupied by transients and visitors. I like to think it belonged to Andreas & Elvira Scott, Native Americans who were listed in an 1880 census of the area. If you know anything more, please contact me and give me the scoop.

Thunder Spring Trail Directions 65
Continue past the cabin and continue the descent.
Thunder Spring Trail Directions 66
There's a nice downhill with views of the surrounding hills.
Thunder Spring Trail Directions 67
When you see the intersection of the Cedar Trail on the right, hike down it. Keep your eyes open, it's easy to miss the trail turnoff.
Thunder Spring Trail Directions 68
Now you are on the Cedar Trail.
Thunder Spring Trail Directions 69
The trail is rolling as it follows the ridge.
Thunder Spring Trail Directions 70
And then starts downhill through some massive cedar trees.
Thunder Spring Trail Directions 71
As you approach the bottom of the hill, the trail gets steeper.
Thunder Spring Trail Directions 72
And then you are at the bottom. Make the left at the t-junction.
Thunder Spring Trail Directions 73
And here's Doane Pond again.
Thunder Spring Trail Directions 74
And then you'll cross the bridge where you first started. Cross over and make the left to head back to the parking area.
Thunder Spring Trail Directions 75
And here you are at the end of the hike!

Need More Info?

This Guide Was Written by Cris Hazzard

Cris Hazzard 4 Mile Trail Yosemite
Hi, I'm Cris Hazzard, aka Hiking Guy, a professional outdoors guide, hiking expert, and author based in Southern California. I created this website to share all the great hikes I do with everyone else out there. This site is different because it gives detailed directions that even the beginning hiker can follow. I also share what hiking gear works and doesn't so you don't waste money. I don't do sponsored or promoted content; I share only the gear recommendations, hikes, and tips that I would with my family and friends. If you like the website and YouTube channel, please support these free guides (I couldn't do it without folks like you!). You can stay up to date with my new guides by following me on YouTube, Instagram, or by subscribing to my monthly newsletter.