San Francisco International Airport

San Francisco International Airport (SFO) is the second-busiest airport on the U.S. West Coast and one of the principal transpacific gateways of North America, handling 51.3M passengers in 2024. Located 21 km (13 mi) south of downtown San Francisco in San Mateo County at just 13 ft (4 m) elevation on reclaimed San Francisco Bay tidal flats, SFO serves the San Francisco Bay Area's concentration of technology capital — a demand sink for premium-cabin travel that gives the airport one of the highest average-ticket-price profiles of any U.S. hub. SFO is United Airlines' principal transpacific hub and one of its largest domestic bases. United's Terminal 3 and International Terminal G operations host its full Asia-Pacific and Oceania widebody network, including the airline's longest sustained route in recent years, SFO–Singapore. Alaska Airlines, Delta, and American Airlines all operate substantial SFO franchises. SFO's runways — four in total (01L/19R, 01R/19L, 10L/28R, 10R/28L), arranged in two closely spaced intersecting pairs — are the tightest geometry of any major U.S. airport, with 750 ft between each parallel pair. Low-visibility operations restrict arrival rates sharply during marine-layer fog events, making SFO chronically weather-constrained and the largest contributor to West Coast air-traffic delays. SFO is architecturally distinctive. The International Terminal — opened in 2000 and designed by Skidmore, Owings & Merrill — is the largest international terminal in North America by square footage and features a signature curvilinear roof that spans the approach road without interior columns. The San Francisco Museum operates one of only three museums accredited by the American Alliance of Museums to be located within an airport. A USD 3.6 billion T3 and T1 rebuild is progressing through phased reopening through 2027.