High Quality Content by WIKIPEDIA articles! Route 110, consisting of two segments of State Route 110 (SR 110) joined by Interstate 110 (I-110), is a state highway in the Los Angeles area of the U.S. state of California, mostly built to freeway standards. The entire length of I-110 (which ends at I-10), as well as SR 110 south of the Four Level Interchange with US 101, is the Harbor Freeway, and SR 110 north from US 101 to Pasadena is the historic Arroyo Seco Parkway, the first freeway in the United States. The entire Route 110 connects San Pedro and the Port of Los Angeles with Downtown Los Angeles and Pasadena. I-110 is one of two 3 digit interstate designations to appear on opposite coasts. I-280 in California and New Jersey is the only other one.