The Interstate 505 number was also used for a never-built spur in Portland.

Interstate 505 connects Interstate 5 to Interstate 80 for drivers traveling west to the San Francisco Bay Area and Napa Valley region or from the west heading north to Redding and surrounding areas. I-505 is primarily a rural interstate but does travel through the town of Winters and near the city of Vacaville, which is its southern terminus.

Primary cities

• Dunnigan
• Winters
• Vacaville