US Route 101 also known as Highway 101, The 101 in Southern California, and simply 101 in Northern California, is one of the last remaining and longest U.S. Routes still active in California. 101 was also one of the original U.S. Routes established in 1926.

The Southern California dialect tends to dictate that "The" precede all freeway numbers, while Northern California dialect tends to dictate that freeway numbers omit the word "The". Often, it is an easy way to tell which part of the state a person originates from.

The south terminus of U.S. Highway 101 is in Los Angeles.

101 is notoriously unpleasant during rush hour between San Francisco and San Jose. Some prefer to take Highway 280.

The dragon's vein of the West coast. The easiest hitchhiking anywhere in America. Part of it traces the old Lincoln highway as well.