Interstate 5

Interstate 5, often called I-5, is the main north–south Interstate Highway along the West Coast of the United States. It runs close to the Pacific coast from Mexico all the way to Canada. This important road goes through three states: California, Oregon, and Washington. Big cities like San Diego, Los Angeles, Sacramento, Portland, and Seattle are all connected by I-5.

I-5 is special because it is the only Interstate highway that reaches both the Mexican and Canadian borders. When you travel south past the Mexican border near San Diego, the road becomes Mexican Federal Highway 1 and continues to Tijuana. When you go north past the Canadian border in Blaine, Washington, the road changes into British Columbia Highway 99 and heads to Vancouver.

The highway was created in 1956 as part of the Interstate Highway System. But before that, there were older roads called auto trails, like the Pacific Highway, built in the early 1900s by the same three states. Later, in 1926, this route became U.S. Route 99. I-5 mostly follows the same path as US 99, with a few changes near Los Angeles and in the Central Valley of California. Building I-5 took many years, from 1956 to 1978.

Route description

I-5 is a major highway that runs 1,381 miles from the Mexican border to the Canadian border. It goes through California, Oregon, and Washington, connecting big cities like San Diego, Los Angeles, Sacramento, Portland, and Seattle. The road has many lanes in busy areas and fewer in rural places.

The highway starts at the Mexican border and goes through San Diego, Los Angeles, and other cities in California. It then moves north through Oregon, passing through Portland before entering Washington. In Washington, I-5 goes through Seattle and ends at the Canadian border, where it becomes a road in Canada.

History

A large part of Interstate 5, from Stockton, California, to Portland, Oregon, follows an old trail called the Siskiyou Trail. This trail was built on paths used by Native American people to travel between the Pacific Northwest and California's Central Valley. In the 1820s, trappers from the Hudson's Bay Company used this route to travel between Washington state and California. Later, stagecoaches and railroads also used this path. By the early 1900s, automobile roads were built along the same route, leading to the Pacific Highway. This highway was the direct predecessor to US 99, which later helped shape the route of today's I-5.

One big change from the old US 99 route is the Westside Freeway in California's Central Valley. This new freeway was built to create a faster and more direct path, bypassing cities like Fresno and Bakersfield. The last part of I-5 to be built was this section in the Central Valley, which opened near Stockton, California, on October 12, 1979. This completed the first continuous freeway connecting Canada and Mexico. It cost about $2.3 billion at the time to build all of I-5.

Over time, parts of I-5 needed repairs due to heavy traffic. In 2013, a bridge over the Skagit River in Washington collapsed, but it was quickly fixed. In 2017, an Amtrak train derailed on a bridge over I-5 near Tacoma, blocking some lanes.

Today, the I-5 corridor is part of efforts to support electric vehicles. States like California, Oregon, and Washington have built charging stations along I-5 for electric cars and trucks, helping make travel along the West Coast cleaner and greener.

Junction list

The Interstate 5 highway connects to many other roads as it travels through California, Oregon, and Washington. In California, it links to important roads near cities like San Diego, Los Angeles, and Sacramento.

In Oregon, I-5 connects to highways around Eugene, Albany, and Portland.

Finally, in Washington, the highway meets other routes near Tacoma, Seattle, and Everett before reaching the border with Canada.

Auxiliary routes

Interstate 5 has many smaller roads that connect to it, called auxiliary routes. These roads help drivers get to places like San Diego, California, Los Angeles, and Portland. Some of these smaller roads are I-105, I-405, and I-205.

Some planned roads, like I-305 and I-505, were not built because people in the area did not want them.