Pacific Coast Highway
While California Highway 1 doesn't start until just south of Dana Point in Orange County, it's worth your time to start at the southern end of the California coast in San Diego. San Diego offers many interesting attractions to the visitor in the neighborhoods away from the beach, such as Balboa Park, Downtown, and Old Town, but if you're just interested in seeing coastline then a worthy place to start is Cabrillo National Monument at the tip of Point Loma. There, you can get a gorgeous view of San Diego, the Bay, and the ocean, and learn about some of the history of the area. Also in the monument is a lovely tidepool area at the base of the ocean cliffs.
Heading north, you can drive along the beaches in the communities of Mission Beach, Pacific Beach, and La Jolla (La Jolla also has a scenic sea coves), or just drive up I-5 and skip the beaches. If you want to take a slower, yet far more scenic route along the coastal beaches, get down to the coast highway near Torrey Pines State Park, between La Jolla and Del Mar. Torrey Pines makes a scenic stop, with hills and cliffs overlooking the coast and trails leading down to the beach. Continuing north along the coast will take you through the lovely towns of Del Mar, Solana Beach, Encinitas, Carlsbad and Oceanside, where you'll drive right next to the coast and over a few nice lagoons connected to the ocean.
In Oceanside, you'll have to get on to I-5 to continue driving north. Just proceed on the Coast Highway through Oceanside until you get to the I-5 exit.
Orange and Los Angeles Counties
In San Clemente, you can get off I-5 at the El Camino Real exit and drive by the Capistrano Beach until you get to California Highway 1. Head north of Highway 1 through Dana Point, Laguna Beach, Newport Beach and Huntington Beach before crossing over into Los Angeles County. As you enter Long Beach, Highway 1 heads inland to cut through the South Bay region of Los Angeles County. Hwy. 1 rejoins the coast near Redondo Beach and continues slightly inland through Hermosa Beach, Manhattan Beach, El Segundo and directly under a runway at Los Angeles International Airport.
Be aware that during times of moderate to heavy rain, the eastbound I-105 onramp just south of the Sepulveda Tunnel at Los Angeles International Airport floods, forcing drivers intending to use the freeway to suddenly merge back onto the PCH. This often causes long delays on the southbound lanes of PCH/Sepulveda from the Lincoln Boulevard-PCH/Sepulveda Boulevard fork until the southern end of the tunnel. Allow yourself at least a half a hour more time to get through the tunnel on rainy days.
Further, be careful on the stretches of PCH that go through Manhattan Beach, Hermosa Beach and Redondo Beach -- there are many uncontrolled "zebra crossing" crosswalks that pedestrians can make use of -- at times, they have popped out onto the street with little warning. The area is also notorious for pedestrians jaywalking across the highway to get to buildings on the other side of the street. So be sure to keep your eyes peeled and practice defensive driving techniques while on the PCH in the Beach Cities.
From Malibu, Hwy. 1 continues along the coast through Point Mugu State Park to Oxnard. Before reaching Oxnard, the road passes by Mugu Rock, formed by the cut the road made through the mountain. After Mugu Rock, the road travels inland through Oxnard north to US-101. Get onto US-101 and heads west through Ventura, where it rejoins the coast. US-101 continues along the coast through Carpinteria, Santa Barbara and Goleta. At the Gaviota State Park, US-101 breaks away from the coast and Hwy. 1 restarts, breaking away from US-101. Hwy. 1 heads north through Lompoc and Guadalupe before rejoining the coast at Grover Beach. At the northern end of Grover Beach, Hwy. 1 merges with US-101 again which proceeds through Pismo Beach before breaking away from the coast to head north to San Luis Obispo. There, Hwy. 1 splits off of US-101 again, traveling northwest to the coastal community of Morro Bay. Hwy. 1 continues along the coast through Cambria, San Simeon, home to the Hearst Castle, along the very scenic cliffs of Big Sur. Several miles north of Big Sur, Hwy. 1 crosses over the beautiful Bixby Creek Bridge and the less famous but still beautiful Rocky Creek Bridge.
From there, Hwy. 1 continues through Carmel, then as a freeway past Monterey and Marina before becoming a two-lane road near Castroville, and then as a freeway again past Watsonville to Santa Cruz. After Santa Cruz, the road becomes a rural road winding along the coast again to the San Francisco Peninsula.
Hwy. 1 continues as a rural road through several communities including Half Moon Bay. As the highway approaches Pacifica, Highway 1 becomes a freeway segment through Daly City before breaking off as a city street, Junipero Serra Blvd, in San Francisco. Shortly after exiting off the freeway, Hwy. 1 becomes 19th Avenue through the Sunset district into Golden Gate Park. In the park, Hwy. 1 becomes Park Persidio Blvd through the Richmond district and into the Presidio park, where it merges with US-101 again. Shortly after exiting onto US-101, you'll drive over the world-famous Golden Gate Bridge over the San Francisco Bay into Marin County. US-101 continues past Sausalito and Marin City, where Hwy. 1 splits off of US-101 again, heading west to the coast at Muir Beach before running north along the coast past the Point Reyes National Seashore.
Hwy. 1 continues along the coast, breaking off briefly to go through the town of Valley Ford before rejoining the coast at Bodega Bay. It heads north through Fort Ross, Point Arena, Elk, Mendocino and Fort Bragg. After passing through the small town of Rockport, Hwy. 1 breaks away from the coast, finally ending at US-101 in the town of Leggett.
US-101 continues north through Garberville, Humboldt Redwoods State Park and Fortuna before rejoining the coast just before Eureka. US-101 continues along the coast through Arcata, McKinleyville and several small towns before finally reaching Redwood National Park, home to the world's tallest trees.
This road is quite isolated. Once south of Carmel there are no other highways connecting route 1 to the interior until you get to route 46, over 90 miles away. Be prepared to drive slowly for about two to three hours and have your wits about you. You will be driving along sharp hairpin curves atop very steep ledges and high cliffs.