Perhaps no place on earth better illustrates two meanings of the word “bluff.”

Physically, it is a bluff — a high, steep bank — on the edge of the Pacific Ocean, at the most southwesterly point of the continental United States.

The peacefulness is also a bluff — a deception. On one hand, a typically sunny Southern California afternoon beckons visitors with roar of the surf, the cry of the sea gulls, the Pacific coast vista — seemingly endless to the north, and a sleepy village and bullfighting ring to the south. A park — Border Field State Park — green lawn, picnic tables, barbecues, children playing.

Now, here’s the deception: the fence. It snakes out of the hills

Beach bluff from Border Field State Park.

and into the surf. This is the border between the United States and Mexico. Border Patrol officers are on duty.

At night, it’s brightly lit and more U.S. officers cruise the hills in sport-utility vehicles, a battle zone within sight of downtown Tijuana. San Diego’s skyscrapers light up the horizon.

But we’re visiting during the day, when the Tijuana River Valley can be enjoyed as a remarkable preserve in the middle of two great international cities.

Over the years this area has been a Naval bombing range and was envisioned as a marina. It has a reputation as a place where sewage flows and international politics have made it a sometime flash point.
But the valley is still a place that can and should be enjoyed as one of the last and best preserved wetlands on the coast.

Ride a horse on the beach. Look up the coast and see much the same view as Native Americans enjoyed before the Spanish arrived.

No condos, no freeways, except off in the distance. And all about 20 minutes from downtown San Diego, which is barely visible on a clear day.

To get there, head south on Interstate 5. Just a couple of exits before the border, look for Dairy Mart Road. Named for the long-gone Dairy Mart Dairy (which, along with others, such as Hages and Golden Arrow, used to home-deliver milk), the quick right turn after exiting Interstate 5 takes drivers almost instantly out in the country.

The river quickly makes its presence known, as a fairly new bridge takes Dairy Mart Road south. On the left, a sod farm and a model airplane field let you know you’re not in the city any more, although straight ahead, on the other side of the fence, traffic buzzes on Baja’s Highway 1. Reeds and coastal sage scrub mark the Tijuana River.

As Dairy Mart Road curves, it changes to Monument Road, honoring the U.S.-Mexico border marker at the park.

The road curves gently around the south bluff of the river’s gorge. Quickly, you’ll notice the first of many stables. Hundreds of horses are boarded and bred in the valley.

Continue down Monument Road, such as it is, past Hollister Street. Bumpy, pitted when paved, rocky and potholed when dirt, it is passable. It is not passable after a heavy rain, so if the road is a pond, come back another day. Here’s an opportunity for those with SUVs to actually drive off the pavement, but I’ve got a two-seat sports car and took it with no problem. Just keep your eyes open and slow down.

Driving north, the farms end and the preserve begins. All told, the combined Tijuana River Valley Regional Park, part Tijuana River National Estuarine Sanctuary, Border Field State Park and Tijuana Slough National Wildlife Refuge cover 2,500 acres. One of 23 estuarine reserves in the country devoted to education and research, it is a place to bird watch, hike, horseback ride, and enjoy the coast of our ancestors.

Past the park entrance, the road curves south to the Border Field State Park, up on our bluff. After driving for a few miles through the middle of nowhere, it seems a bit surprising to turn into a parking lot for a very conventional park — picnic tables, barbecues.

To the north is the reserve, the west the ocean, the south Tijuana’s saucer-shaped Bullring by the Sea and adjacent neighborhood, and to the east the mountains and South Bay cities.

Farther north, the skyscrapers of downtown San Diego can be seen on a clear day. Beyond, Point Loma rises Gibralter-like out of the sea.

Take some time to enjoy the view and check out The Monument — one of a chain that stretches to the Gulf Coast of Texas marking the border between the United States and Mexico. Look at the border fence. Talk with the friendly Border Patrol agents. And chat with the folks on the other side of the border through the mesh fence.

The view is spectacular. A wide, sandy beach is a short hike down the hill. And, if the water is clean, it’s OK to swim.

Heading back, retrace your route to Hollister Street and turn left. Stables rent horses for the day; one even has guided tours to the beach. Riding there, I’m told, is a unique experience for both horse and rider.

Continuing north, you’re in the City of San Diego community of Nestor, which lies between the City of Imperial Beach and Interstate 5. It’s hard to see, but you’re circling one of the lesser known Naval bases in San Diego, the Imperial Beach Naval Auxiliary Landing Field, also known as Ream Field.

We’ve now driven around the preserve and are about to learn about it. The Estuary Visitors’ Center is just off Imperial Beach Boulevard. Follow the signs and turn left at 3rd Street and around to the center. Open daily, the center offers exhibits on the flora and fauna in the estuary, as well as a fabulous view of the marsh.

Friendly park service employees point out sites and birds, and paths lead away from the center. Staff and an active volunteer program provide nature walks and bird walks on weekends, a speaker series on Friday and for kids a Junior Rangers program on Thursday afternoons.

The estuary is home to endangered species such as the California Least Tern and American Peregrine Falcon. Bring your binoculars. Estuaries like Tijuana used to be located every few miles along the coast — almost every place where a river met the sea. However, most have been developed, leaving few places for migrating birds and other wildlife.

The last view we’ll have of the estuary on today’s drive is from across the slough, on Imperial Beach’s Seacoast Drive. Condos line the beach, but the view of the estuary is open. Parking is available so take advantage of the opportunity to hike both the beach and estuary.

Do spend some time in Imperial Beach, a funky beach town that hasn’t been too gentrified — the rough edges make it interesting. The pier and adjacent park have recently been spruced up, and while there are a few new shops, this is IB. If you’re looking for Seaport Village, you won’t find it here.

Continue on to Coronado on the Silver Strand, a skinny strip of land that separates the bay from the ocean. There’s more traffic these days (like everywhere else), but taking the Strand lets you see some more open space in the middle of San Diego. The county’s Ecological Research area is just north of the old salt ponds (extracted salt is used for water purification and other industrial processes). The paved bicycle path (on the old railroad right-of-way) and the Coronado Cays development (exclusive waterfront homes) are along the way.

The Silver Strand State Beach is one of the nicest ones (day use, $4) and one of the few places with RV parking right on the beach.

Coronado is next. This beach town, which starts with the Hotel Del Coronado and Coronado Shores towers, is worth a day to explore.

We can’t cover it here, but if you continue through town to the end of Orange Avenue, there’s a bit of San Diego transportation history. One of the old ticket booths is all that’s left of the San Diego-Coronado car ferry, which quit in 1969 when the bridge opened. To the south is the Old Ferry Landing development, a collection of shops and restaurants.

From here, it’s just a few blocks back to 4th Street and over the bridge to San Diego.
Today’s drive has visited several spots of nearly unspoiled beauty, harkening back to the days before San Diego and Tijuana became a megalopolis. We’ve wound our way from the controversial border and up the coast to the lovely seaside community of Coronado. Hope you didn’t forget your binoculars and camera.