Los Penasquitos Lagoon

One of my favorite places to explore over the past 30 years is the Los Penasquitos Lagoon at Torrey Pines State Natural Reserve. Can I take you on tour?

Ok! Let’s go!

Los Penasquitos Lagoon

Located between Del Mar to the north and the border of San Diego to the south, the Los Penasquitos Lagoon is a 510-acre coastal salt marsh estuary.

—>San Diego Lagoons and Nature Centers<—

Meaning “The Little Cliffs” in Spanish, the Los Penasquitos frames the northern part of the Torrey Pines State Natural Reserve.

The Los Penasquitos Lagoon is a Salt Marsh?

Torrey Pines State Natural Reserve

Los Penasquitos Lagoon is one of the last salt marshes in southern California. The lagoon supports many plants and animals, including seven threatened or endangered species.

Another interesting fact is that this lagoon also serves as a refuge for migratory birds that use the Pacific Flyway.

—>Best San Diego Birding Hotspots<—

Since joining the State Park System, there have been quite a few changes to help increase the overall tidal flow here at the Los Penasquitos Lagoon.

Let’s now have a look.

button map los penasquitos lagoon Parking Fees Information

Places nearby–   Torrey Pines State Beach

Torrey Pines State Natural Reserve

Activities– Hiking, bird watching

Los Penasquitos Lagoon History

Development within the lagoon in the 1880s and the 1930s has modified the lagoons’ hydrology process.

There are several reasons for how this eventually happened.

Railroad Tracks over Los Penasquitos Lagoon

Sante Fe Railroad Track at the Los Penasquitos Lagoon

First, in 1925, the Sante Fe Railroad built a single-track roadbed causeway embarkment down the center of the lagoon for its Surfline.

Can you believe that this track is still in use today daily?

Train track over Los Penasquitos Lagoon

The embarkment severely restricted the normal historical lagoon drainage for the first time, ultimately changing the tidal flow.

A New Highway 101 Bridge Over the Los Penasquitos Lagoon

Los Penasquitos Lagoon man in front
Do you notice all the pilings on the original bridge? (circa 1993)

In the 1930s, the Pacific Coast Highway, known as US Route 101, was expanded, the roadbed along the beach heightened, and a bridge built over the lagoon’s mouth.

The waterway under the bridge would continually get clogged with sand and debris due to the 72  wooden pilings. This debris, in turn, would impact the water flow between the ocean and the lagoon.

In 2005, a new bridge was built for uninhibited water flow.

Do you notice that there are only four cement pilings? Because of this, the lagoon being closed off by sand and debris doesn’t happen anymore.

Highway bridge over Los Penasquitos Lagoon Under Bridge Los Penasquitos Lagoon inlet

Inlet On Beach Torrey Pines State Beach
Uninhibited water flow is a beautiful thing!

Inlet meets Beach Los Penasquitos Lagoon

Due to the very low tide, the tidal flow out to the beach is more vital than usual.

Fun fact- My husband and I would consistently come out here to Torrey Pines State Beach back in the early 1990’s when we were dating.

One of our favorite things to do was to go at night with flashlights.  Looking for gray smoothhound sharks, we would shine the light into the mouth of lagoon. Their eyes would glow green with the reflection of light.

Gray Smoothhound Shark Los Penasquitos Lagoon

Let’s now look at the lagoon’s mouth from on top of the bridge on Highway 101.

Beach Bridge View Torrey Pines State Beach
The inlet was extra large today due to the extreme high/low tides.

Do you see the metal pole sticking out of the water towards the left? That monitor keeps track of the tidal flow in and out of the lagoon.

Los Penasquitos Lagoon Inlet Meets Beach

North Beach Entrance Parking Lot at Torrey Pines State Beach

North Parking Lot Los Penasquitos Lagoon

In 1983 the Los Penasquitos Lagoon Foundation was established. The primary function of this foundation is to keep the mouth of the lagoon open, improve circulation, and restore critical habitat.

According to the Los Penasquitos Lagoon Foundation and the State Coastal Conservancy, the fully paved North Parking Lot in 1968 altered the lagoons’ hydrology (water circulation).

Could this lagoon ever catch a break? First, off the railroad, clogged bridge pilings, and finally a cement parking lot. All three structures wreaked havoc on the water circulation!

North Parking Lot VIew Across Street
View the north parking lot from across the street.

Street View Lagoon across from highway bridge North Parking Lot view lagoon Torrey Pines State Beach

Los Penasquitos Inlet Many Birds in Lagoon
Look at all of the birds!

Continuing from the North Parking lot and following Carmel Valley Road, there is an unofficial path in which you may view the lagoon from behind a barrier. Let’s go!

Los Penasquitos Lagoon outside trail Los Penasquitos Lagoon Mid Trail Los Penasquitos Lagoon Mid Trail Los Penasquitos Lagoon Beginning Trail

Los Penasquitos Lagoon Trails

Los Penasquitos Boundary-information-sign

Although almost all of the lagoon is off-limits to the public, one trail- The Marsh Trail- is open to exploring!

—>Torrey Pines Trail Guide<—

To reach this trail, you must start at North Torrey Pines Road (HWY 101).

You will find the trailhead not that far south on the east side of the road. The trail winds around the western side of the Reserve, finally ending up in the industrial area of Sorrento Valley.

Los penasquitos lagoon upper view from Reserve trail
Marsh Trail is in the front. Do you notice the north parking lot in the far background?

This trail is not a loop, so you must turn around and return, keeping that in mind. If you go to the end, the roundtrip would be about 4 miles.

There are many plants and animals to look out for, so keep your eyes open!

—>Los Penasquitos Lagoon Field Guides<—

My Special Place-Los Penasquitos Lagoon

Los Penasquitos Lagoon 1990 old bridge

Well, thank you so much for joining me on a tour of the Los Penasquitos Lagoon. As you can see, it is not enormous but has character.

Check back later as I plan to hike on the Marsh Trail shortly!

As I have previously stated, this lagoon has always held a special place in our hearts. I feel incredibly fortunate to have seen so many improvements and witnessed this lagoon’s transformation over the last 30 years.

The new bridge has a lot to do with this, so thanks to the new bridge! Thank you for allowing more water into the lagoon and improving the circulation.

Los Penasquitos Lagoon inlet beach

Special thanks go to the Los Penasquitos Lagoon Foundation for their hard work and dedication to preserving and researching this environment.

I hope you may one day witness the Los Penasquitos Lagoon in person. San Diego has many beautiful places to discover, especially the coastline!

Please leave any comments or questions that you may have down below.

Until next time!


3 Replies to “Los Penasquitos Lagoon”

  1. It looks like a nice place to go for a walk and take in a little bit of scenery. I do like to watch birds from time to time. Are there any bird huts located there to spy on them in the marsh?

    1. Thank you for visiting Owain. I am not sure if there are any bird huts on the Reserve, especially at the Lagoon. I have read that on the Marsh Trail there are some big trees, so I suppose that would help with some cover to watch the birds in the marshland. I will have to get back to you after I try the trail out! Thanks again for your question. I do have a suggestion on where you can go that does have some natural barriers to observe bird up close. https://70milesofcoast.com/a-walk-around-buena-vista-lagoon

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