Interstate 5 is the only continuous freeway connecting Mexico and Canada through the United States, running 1,381 miles from San Ysidro at the California-Mexico border to Blaine, Washington at the Peace Arch crossing into British Columbia. It is the dominant freight corridor of the West Coast, moving produce out of the San Joaquin Valley, container traffic between the ports of Long Beach, Oakland, and Tacoma, and timber and agricultural products from the Pacific Northwest.

The route splits cleanly into three personalities. From San Diego through Los Angeles and up the western edge of the San Joaquin Valley, I-5 is largely a flat agricultural expressway crossed by the Tejon Pass (Grapevine) at 4,144 ft — a 6% grade that closes for snow several days each winter. Through Northern California it climbs into the Cascades over Siskiyou Summit (4,310 ft), the toughest sustained climb on the entire interstate, before descending into the Rogue Valley of Oregon. From Eugene north through Portland, Olympia, Seattle, and the Skagit Valley, I-5 becomes a dense urban interstate routinely choked with congestion in the four-hour Portland-Seattle-Tacoma chain.

For commercial operators, I-5 is the lifeline of West Coast logistics. CHP and Oregon DOT enforce truck-specific speed limits and bridge weight restrictions aggressively, and the Siskiyou-Shasta corridor has more weigh stations per mile than any other Western interstate. Chain controls are routine November through April from the Grapevine north.

  • Only US interstate that touches both the Mexican and Canadian borders
  • Crosses Siskiyou Summit (4,310 ft) — the highest sustained grade on any US interstate
  • Tejon Pass / Grapevine (4,144 ft) closes 5-15 times per winter for snow
  • Carries the bulk of Port of Long Beach and Port of Tacoma container drayage
  • Routes through downtown Sacramento via the I-5 / Capital City Freeway interchange
  • Designated CARB-compliant corridor in California — pre-2010 trucks face restrictions
  • Concurrent with no other interstate for any significant distance — runs solo end-to-end