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Santa Ana Mountains

Reviewed August 2026

Limestone Canyon Regional Park is an incredibly beautiful area to hike, but it’s also home to a famous area called ‘The Sinks,’ also known as ’the little Grand Canyon of Orange County.’ Limestone Canyon is not always open to the public, but this easy trail guide will show you how to visit and see The Sinks for yourself.

Distance: 9 mi
Difficulty: Moderate
Total Climbing: 850 ft
Time: 3–4 hrs

Gear Fitness clothes or light hiking gear is fine here. Bring a minimum of 1L of water. You can see all the gear I use on a hike like this here.

When Winter and spring are best.

In This Guide

Video

Limestone Canyon Regional Park - The Sinks

Trailhead

Limestone Canyon Regional Park is located in Orange County, CA, in the foothills of the Santa Ana Mountains.Before visiting Limestone Canyon Regional Park, you must register for an open event.

Visit LetsGoOutside.org
Go to “Activities” and filter by “Limestone Canyon Nature Preserve”
Find a match for the day that you want to visit. There are two types of hikes.

Open hikes allow you to pick any open trails you’d like and hike freely.

Docent-led hikes are traditional group hikes led by an expert. These hikes are great because you’ll usually get a guided tour along the way.

Note that the hikes have difficulty ratings; you should find one that matches your level. Hikes can have different starting areas. The website has a downloadable map of the current trails and starting areas.

Limestone Canyon Regional Park Ranger Display — You’ll be able to see lots more on a docent-led group hike. They point out animals, plant species, fossils, bones, and anything else interesting. They’ll also be there to answer any questions.

Maps

Limestone Canyon Trail Sign — Limestone Canyon is well-marked, with trail signs at all the trail junctions.

If you go on a general open day, I recommend hiking to The Sinks, aka the Mini-Grand Canyon, the main attraction. This guide has directions for that hike. There are many more trails and you could include others to choose your own adventure as well.

Limestone Canyon Trail Closed — Under certain circumstances, some trails can be closed. Please print the map at home or save it to your phone before leaving. Cell reception in the park is spotty.

Directions

Limestone Canyon Historic — This area was used for cattle grazing from the 1800s until 2010 when it was turned into a park. This photo, with Saddleback Mountain in the background, is from 1892.

The Sinks Hike Directions 4 — At about 2.2 miles, make the left onto the Raptor Trail and do a short climb.

Limestone Canyon Rehab — From the climb, there are nice views into Limestone Canyon. The area is actively being restored to its native habitat after being grazed by cattle for over 100 years.

The Sinks Hike Directions 5 — When you reach the junction with Limestone Ridge Trail, make the right.

The Sinks Hike Directions 6 — The Limestone Ridge Trail offers epic views into Limestone Canyon and into the Santa Ana Mountains.

The Sinks Hike Directions 7 — Avoid any side trails and stay straight on Limestone Ridge.

The Sinks Hike Directions 8 — At around 4 miles you’ll get views into The Sinks on your right.

The Sinks Hike Directions 9 — And at about 4.4 miles, look for the trail on the right up to the East Sinks Viewing Area.

The Sinks Hike Directions 1 — Once on the platform, you’ll have panoramic views of The Sinks.

Limestone Canyon Regional Park The Sinks Featured — The Sinks were formed by erosion and are between 20-40 million years old.

Limestone Canyon and The Sinks Hike Guide