Thanks to poster ALTippet for this information :-) 

Redwood National Park is located approximately 300 miles to the north of the San Francisco Bay area, and by car it takes about 5-6 hours to reach it via Highway 101, the fastest route. For those visitors who would love to see redwood trees but simply do not have the time to visit the actual National Park, there are several places to see big redwoods that are much closer to San Francisco.

Visitors can enjoy young coast redwoods transplanted from the Santa Cruz mountains right in downtown San Francisco at the Transamerica Pyramid Redwood Park. However, you have to venture outside the city for old growth redwoods. There are several options near SF. 

Since Muir Woods is the closest to SF and a National Monument, it is very popular and the de facto choice for SF visitors. There are also five "old growth" alternatives to Muir Woods that are a lot less crowded and much quieter:

-- Armstrong State Natural Reserve  is highly recommended even though it requires an extra hours drive further north. Not only is it larger than Muir Woods (800 acres to 250 acres) in Muir Woods), it also has the taller tree (Parson Jones in Armstrong is 310 feet tall compared to 260 feet for the tallest tree in Muir Woods). 

-- Henry Cowell SP is a good alternative to Mur Woods for those traveling to Monterey as it is about a 15 minutes detour off the freeway. It also has taller trees (285 feet) than Muir Woods.

-- Big Basin SP rewards those who make the long winding drive with larger groves and the tallest redwood tree in the Bay Area (the Mother of Forest tree at Big Basin is 329 feet tall).

-- Memorial Park is managed by San Mateo County and located in Pescadero. The campground is popular as it is located in the middle of a small grove of old redwoods. It is a 9 mile detour off Route 1 on the way from San Francisco to Santa Cruz.

-- Samuel P. Taylor SP is not as highly recommended as it only has one old growth tree within the second generation redwood forest. However, the park is very convenient for those visiting Point Reyes and the lone old growth tree is large enough to stand in.