Interstate 505 (I-505) is a north–south auxiliary Interstate Highway in the Sacramento Valley in Northern California. It is a spur auxiliary route of I-5 that runs from near Dunnigan south to I-80 in Vacaville. I-505 is primarily a rural Interstate, but travels through Vacaville and the city of Winters. The highway is the primary route connecting the San Francisco Bay Area and the northern Sacramento Valley, bypassing Sacramento and its attendant city traffic. Thus, it is a major route for travelers heading directly from the San Francisco Bay Area to the Pacific Northwest.