Diemer Trail is a 10.5 kilometer heavily trafficked loop trail located near Yorba Linda, California that features beautiful wild flowers and is rated as moderate. The trail offers a number of activity options and is best used from March until October. Horses are also able to use this trail.

Distance: 10.5 km Elevation Gain: 207 m Route Type: Loop

kid friendly

hiking

horseback riding

nature trips

walking

bird watching

running

views

wild flowers

wildlife

bugs

no dogs

This park is temporarily closed to vehicular access, meaning there are no parking facilities and parking on roadways is prohibited to protect public health from the COVID-19 pandemic. As of January 06, 2020, users have reported that there are temporary closures in this area. Please consult the park's website before visiting. Rolling Hills easy access to great hiking in Orange County. Entering the Chino Hills State park from the south Entrance at Rim crest Dr. puts you right in the middle of a great park with an abundance of wildlife and scenery. The hike starts off on the south ridge trail from Rim crest dr. Hike west along the south ridge trail as it allows you views of Orange County. At about 2miles, the road forks. follow to the right on Diemer trail. Diemer trail winds down the hill for about a quarter mile. At the bottom, head east on Telegraph Canyon back 2 miles until you see the trailhead for easy street. head south on easy street trail and back to Rim crest dr. The ridge portion offers scenic views but little shaded areas. Telegraph Canyon offers great shaded areas to stop for a snack and cool down. The easy street trail a smaller trail that is off limits to mountain biking, but still be aware as bikers tend to ignore this rule. Easy street is also a moderately steep climb just over .3 mile.

hiking
10 days ago

Great spring evening hike when animals are catching dinners before sunset. We saw a hawk swoop down and snatch a rat on Easy Street, a crow patiently wait and catch a large lizard on Telegraph, and a tarantula hawk wasp (large dark blue wasp with transparent orange wings) dragging a still-kicking tarantula more than 5x its weight along South Ridge. By the way, don’t mess with these wasps because their stings are among the most painful of all insects. They are also along Telegraph.

hiking
no shade
3 months ago

recorded Diemer Trail

hiking
bugs
3 months ago

This is a great alternate ride for me by going down Lytle Canyon from the South Ridge and coming back up Deemer trail to the trail head at home very good ride 6 1/2 miles. This was a bike ride. The ride WEST from Lytle Canyon on telegraph was all downhill barely any paddling at all the rest of it made your legs burn

hiking
3 months ago

Diemer/Lil Cyn/Coyote Trail Loop : From Rim Crest trail head east to Little Canyon. Take Little Canyon down to Telegraph Canyon Road and go west to the Coyote Trail entrance at 1.6 mile mark. Head up Coyote Trail back to South Ridge. Take South Ridge west to Diemer and head down to Telegraph Canyon Road. Take Telegraph east to Easy Street and finish back at Rim Crest. This loop trail can be done with several variations for a hike a tad over 6 miles.

hiking
4 months ago

Saw a coyote again on South Ridge and got pic, but he was far away. Think he was the same one from 4 days ago, on the same hill.

hiking
4 months ago

Saw another coyote on South Ridge that did not run, 20-25 yds away, until I pulled out camera. Darn!

hiking
closed
muddy
5 months ago

Great and lovely hike. I would rate this hike Easy more than Moderate. Didn’t realize the park was closed due muddy/wet ground. Special note: this park is closed 48 hours after a rainstorm. ;)

hiking
muddy
5 months ago

hiking
5 months ago

Nothing unusual, except I did see a coyote on South Ridge just after Little Canyon, so that was cool. Ran before I could take a picture.

running
muddy
5 months ago

hiking
6 months ago

No dogs allowed. Didn’t know till we got there. That’s why we cut it short.

hiking
6 months ago

Not really into it.

hiking
off trail
over grown
7 months ago

Nice hike, just missed my turn to finish the diemer loop trail, but didn’t see anywhere to change direction other than walk straight. Some parts of hike are getting overgrown. I did see a tarantula as well as a rattlesnake.

hiking
8 months ago

Saw 1 tarantula. Started at ridgecrest, got there around 6:45 am. Entire hike took about 2 hours and 30 minutes. If you have this app on while hiking, it’s very easy to follow the trail. Some ups and downs in the first quarter but relatively plane field after that. Would definitely recommend this hike!

hiking
8 months ago

Saw a tarantula

hiking
9 months ago

Decent size rattlesnake and lots of tarantulas today.

hiking
10 months ago

Saw a deer (doe) today and a tarantula. No chance for a picture though.

hiking
over grown
10 months ago

I started and ended this hike from Ridgecrest. Took longer than I anticipated but it was a good workout. Most of the trail is in full sun so get an early start. The junction at Diemer isn’t marked from Southridge but it’s easy to find.

hiking
10 months ago

Lots of Blue-belly Fence Lizards today and three Alligator lizards, which I took pics of. I also saw a coyote but was not quick enough for the picture before it ducked into the bush.

hiking
over grown
11 months ago

hiking
over grown
11 months ago

hiking
over grown
11 months ago

Four tarantulas but no snakes today.

hiking
11 months ago

Great hike. Overcast so it was not too warm. The mustard is drying out but still lots of wild flowers to see. 3 hours all together with a snack break at the Nature Center.

running
Fri May 10 2019

Preparing for a spartan race, I thought I’d get some distance training. For the most part, the trail is open. Only a little portion of the trail is very over grown. Lightly trafficked. Rattlesnakes are out so be alert

hiking
Wed May 01 2019

It’s amazing how much the vegetation has grown since the recent rains. It’s the most that I’ve seen in over 10 years. South Ridge Trail has so much growth you cannot see the OC basin. Even Telegraph Canyon which is normally a dry and dusty dirt road with side vegetation no more than 2 feet tall, is overwhelmed with growth and plenty of shade. Butterflies, birds and bunnies everywhere. Lots of bees too but the plants are so high you can only hear them. A benefit is the mountain bikers cannot zoom by at full speed like they normally do without getting slapped by the mustard plants! If you haven’t been here in a while, now is the time to enjoy before the vegetation browns after summer.

Mon Apr 22 2019

Giving a quick rating to make a comment. I have yet to click on a trail on this app that does not say "no dogs" What gives???

hiking
Fri Feb 08 2019

Great walking trail. Even after the rains we just got the tuts weren’t too bad. I finished right before the sun set on a beautiful clear day.

hiking
Tue Jan 29 2019

This is NOT Diemer Trail. I just used the Diemer map for tracking. I made this loop connecting steep uphill game trail, just north of Easy Street at Telegraph Cyn, with North Ridge Trail. The trail kind of parallels Gilman Trail heading to North Ridge Trail. At the top a small game or cattle trail splits off trail and takes you to Gilman Peak. At Gilman Peak, another game trail heads downhill to the Southeast. This game trail takes you back to Telegraph Cyn Road. Take Telegraph Cyn west to Little Canyon uphill and back to South Ridge Trail. Good amount of elevation gain (1522’) for five miles of trail in this area is good. This is a pretty fun hike. This hike was done on Jan. 29,2019, before these trails got so overgrown.

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