Interstate 380 (California)

Interstate 380
Quentin L. Kopp Freeway
I-380 highlighted in red
Route information
Maintained by Caltrans
Length	3.3 mi[1] (5.3 km)
Existed	1964–present
NHS	Entire route
Major junctions
West end	I-280 in San Bruno
Major intersections	SR 82 in San Bruno
East end	US 101 in South San Francisco
Location
Country	United States
State	California
Counties	San Mateo
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future State highways in California Interstate US State Scenic History Pre‑1964 Unconstructed Deleted Freeways
← SR 371 → US 395

Interstate 380 (I-380) is a short 3.3-mile (5.3 km) east–west auxiliary Interstate Highway in the San Francisco Bay Area of Northern California, connecting I-280 in San Bruno to US Route 101 (US 101) near San Francisco International Airport. The highway primarily consists of only three intersections: I-280, State Route 82 (SR 82/El Camino Real), and US 101. Like the nearby I-280, I-380 never connects to I-80, its parent Interstate Highway. However, there is no rule that says that spur routes need to do so. (Similarly, the spur route I-795 branches off from I-695, a beltway around Baltimore, and is only indirectly linked to I-95.)

I-380 is officially known as the Quentin L. Kopp Freeway, named after the prominent California state senator from San Mateo County. This highway was previously named the Portola Freeway to honor the 18th-century Spanish explorer Gaspar de Portolá, whose expedition in 1769–1770 discovered the San Francisco Bay, from a viewpoint on the Sweeney Ridge located between San Bruno and Pacifica.