High Quality Content by WIKIPEDIA articles! Interstate 605 (abbreviated I-605, officially known as the San Gabriel River Freeway and colloquially referred to as the 605 (the six-oh-five)) is a major north–south Interstate Highway in the Greater Los Angeles Area of Southern California. It is about 27 miles (43 km) in length, and runs from Seal Beach to Irwindale, closely paralleling the San Gabriel River for most of its alignment. The San Gabriel River Freeway is one of the few Southern California freeways not named after a city along its route.