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Total length: 1,382 miles (2,224 km)
Southern terminus: San Ysidro, CA, at Mexican border
Northern terminus: Blaine, WA, at Canadian border
States traversed & length in each:
- California — 797 miles (1,282 km)
- Oregon — 308 miles (496 km)
- Washington — 277 miles (446 km)
Major cities along route:
- San Diego, CA
- Anaheim, CA
- Los Angeles, CA
- Stockton, CA
- Sacramento, CA
- Redding, CA
- Medford, OR
- Eugene/Springfield, OR
- Salem, OR
- Portland, OR
- Vancouver, WA
- Olympia, WA
- Tacoma, WA
- Seattle, WA
- Everett, WA
- Bellingham, WA
Junctions with non-related Interstates:
- Interstate 8: Unnumbered exit at MP 20 in San Diego, CA
(California Interstates currently lack consistent exit numbering.)
- Interstate 710: Unnumbered exit at MP 130 in Los Angeles, CA
- Interstate 10: Multiplex from MP 133 to MP 135 in Los Angeles, CA
- Interstate 210: Unnumbered exit at MP 160 in Sylmar, CA
- Interstate 580: Unnumbered exit at MP 448 near Tracy, CA
- Interstate 80: Unnumbered exit at MP 522 in Sacramento, CA
- Western Interstate 84: Exit 301 in Portland, OR
- Interstate 90: Exit 164 in Seattle, WA
Related loops and spurs:
- Interstate 805 — 29 miles long; 180° loop, east of I-5, bypassing downtown San Diego, CA; termini at unnumbered exits at I-5 MP 1 and MP 31
- Interstate 405 — 73 miles long; 180° loop, west of I-5, bypassing downtown Los Angeles, CA; named “San Diego Freeway” over its entire length; termini at unnumbered exits at I-5 MP 93 and MP 158
- Interstate 605 — 27 miles long; spur that “spears” I-5 (exists on both sides of I-5); southern terminus at I-405 in Seal Beach, CA, and northern terminus at I-210 in Duarte, CA; named “San Gabriel River Freeway” over its entire length; numbered in reverse (zero point at northern terminus, highest numbering at southern terminus); unnumbered exit at I-5 MP 123
- Interstate 105 — 18 miles long; spur from I-605 in Norwalk, CA, to Los Angeles International Airport; called “Century Freeway” over its entire length; unnumbered exit at I-605 MP 17 (does not connect to I-5)
- Interstate 205 — 13 miles long; spur from I-5 east of Tracy, CA, to I-580 west of Tracy; numbered in reverse (zero point at I-580, highest numbering at I-5); unnumbered exit at I-5 MP 458
- Interstate 305 — NOT SIGNED; 5 miles long; spur that “spears” I-5 (exists on both sides of I-5); designation given to the east-west (U.S. 50) portion of Sacramento’s Business I-80 freeway, but the California Department of Transportation (Caltrans) chooses not to sign it; number was assigned when I-80 was re-routed around Sacramento; unnumbered exit at I-5 MP 518
- Interstate 505 — 33 miles long; spur from I-5 at Dunnigan, CA, south to I-80 at Vacaville, CA, for access to the San Francisco Bay Area from the north; numbered in reverse (zero point at I-80, highest numbering at I-5); unnumbered exit at I-5 MP 552
- Interstate 105 — 3.5 miles long; spur from I-5 into downtown Eugene, OR; numbered in reverse (zero point in downtown Eugene, highest numbering at I-5); freeway continues east past Springfield as Oregon Route 126; I-5 Exit 194B
- Interstate 205 — 37 miles long; 180° loop, east of I-5, bypassing downtown Portland, OR; numbering is continuous and does not reset at Washington state line (26 miles in OR, 11 miles in WA); termini at I-5 OR Exit 288 and WA Exit 7
- Interstate 405 — 3.6 miles long; 180° loop, west of I-5, passing through downtown Portland, OR; termini at I-5 Exits 299B and 303B
- Interstate 705 — 1.6 miles long; spur from I-5 into downtown Tacoma, WA; ends just north of downtown at E. 10th St.; I-5 Exit 133
- Interstate 405 — 30 miles long; 180° loop, east of I-5, bypassing Seattle, WA; termini at I-5 Exits 154 and 182
Length I’ve traveled: From southern terminus to CA MP 133 (U.S. 101/Santa Ana Fwy); from CA MP 144 (CA 134/Ventura Fwy) to CA MP 308 (CA 41/Kettleman City)
Pacific — Entire length
California — San Diego, Orange, Los Angeles, Kern, Kings, Fresno, Merced, Stanislaus, San Joaquin, Sacramento, Yolo, Colusa, Glenn, Tehama, Shasta, Siskiyou
Oregon — Jackson, Josephine, Douglas, Lane, Linn, Marion, Clackamas, Washington, Multnomah
Washington — Clark, Cowlitz, Lewis, Thurston, Pierce, King, Snohomish, Skagit, Whatcom
A quick hypertext drive: Ingrained in the American consciousness as “the 5,” as it is commonly called in Southern California, Interstate 5 serves as the main artery of America’s West Coast. It is the only Interstate that truly runs from border to border — a few others come close, but only I-5 reaches to both the Mexican and Canadian frontiers.
Interstate 5 begins at the world’s busiest border crossing, where an astonishing 50 million people cross between Tijuana, Mexico and San Ysidro, CA every year. When I traveled through this border crossing in 1989, I counted more than 20 northbound lanes through the U.S. Customs inspection booths! Eventually, after the Customs station and the I-805 split just north of Customs, I-5 settles down into an eight-lane (three general-purpose and one HOV lane each way) freeway through the southern parts of San Diego. Tracking first to the northwest, then more to the north, it approaches and passes the downtown area. All throughout San Diego County, I-5 generally stays very close to the shore of either San Diego Bay (south of the city) or the Pacific Ocean (to the north), staying a bit further inland in the La Jolla area.
A fairly long stretch of I-5 in northern San Diego County passes through the Camp Pendleton Marine Corps Base, just a couple hundred yards from the ocean shore. Just across the county line into Orange County, near Capistrano Beach, I-5 makes a sharp turn toward the northeast and heads inland for several miles; it eventually turns due north toward Mission Viejo, widening to ten lanes along the way. Turning to the northwest, I-5 approaches the so-called “El Toro Y” (its southern split with I-405), after which it narrows back to eight lanes on its way toward the biggest cities of “the O.C.”: Santa Ana and Anaheim. (Note that I-5 loses the “San Diego Freeway” name at I-405, handing it off to 405; it takes on the name “Santa Ana Freeway” here, from the El Toro Y to downtown Los Angeles.) Angel Stadium, the home of baseball’s Los Angeles Angels, is easily visible from I-5 near the so-called “Orange Crush” interchange with the CA 57 and CA 22 freeways.
Orange County voters’ decision to impose a county sales tax upon themselves in the 1980s and 1990s has led to the construction of a fast, efficient I-5 through the northwestern reaches of that county; it is as wide as 12 lanes at some points. However, just across the county line in Los Angeles County, I-5 remains on its original six-lane alignment from the 1960s; this stretch can be congested almost 24/7. The Santa Ana Freeway does widen to eight lanes again as it gets closer to downtown Los Angeles.
On the eastern edge of downtown sits the appropriately-named East Los Angeles Interchange, where I-5 transitions off the Santa Ana Freeway (handing it off to U.S. Route 101 at that highway’s southern terminus) and joins Interstate 10 for the first two miles on the Golden State Freeway. Handing I-10 off to the San Bernardino Freeway, I-5 continues north, skirting the eastern side of downtown and generally paralleling the often-dry Los Angeles River bed. It also skirts the eastern end of the Hollywood Hills as it passes through Griffith Park, before heading into the San Fernando Valley.
Still generally at eight lanes wide, I-5 collects merging traffic from several other routes in quick succession (CA 170, I-405, I-210) and leaves the San Fernando Valley, climbing through Newhall Pass. It runs through the flatter Santa Clarita Valley for perhaps 10 miles (16 km) before passing the town of Castaic and reaching the so-called “Five-Mile Grade.” Here, the two directions of traffic cross each other and drive to the left of the median for five miles, as the 6% grade’s colloquial name indicates; in fact, each direction follows its own alignment on the hill. The current northbound lanes were built atop the old “Ridge Route” that in its earliest form dated to the 1920s; the southbound lanes were built a few hundred yards to the east as new construction, with a somewhat more gentle downgrade, in the late 1960s. At the top of the hill, another cross-over brings the two directions back to right-side travel.
Continuing as an eight-lane highway, and carrying enough traffic at peak times to warrant same, I-5 spends the next 35 miles (55 km) or so passing through the beautiful Angeles National Forest. While most of I-5 south of the Five-Mile Grade sat at fairly low elevations, generally below 1,000 ft. (305 m), this stretch runs closer to the 4,000-ft. (1,219 m) elevation level. Pyramid Lake and Old Fort Tejon are two major attractions in this region. Just north of Lebec, perhaps seven miles into Kern County, I-5 reaches the top of a treacherous descent called “the Grapevine” after the grapes that grow wild in the area; this four-mile, 6% grade actually features California’s lowest downhill truck speed limit — 35 mph (56 km/h).
Interstate 5 continues to descend, although not as steeply and without the sharp curves that require that speed limit on the Grapevine, for at least another 10 miles (16 km) into the gigantic San Joaquin Valley. It spawns California Route 99, a freeway that serves most of the Central Valley’s major cities, just north of the bottom of the Grapevine; from here, I-5 heads northwest into the middle of nowhere. Finally dropping to four lanes, I-5 goes through nothing other than central California’s fertile farm country for well over 200 miles (320 km). Note that I have not traveled on I-5 north of the California Route 41 exit near Kettleman City; however, from here north, I am aware of many of the highlights of the routing of I-5.
Just north of the Stanislaus/San Joaquin county line, southeast of Tracy, I-5 spawns I-580 to head west and serve the San Francisco Bay Area; I-5 itself turns to the north on a beeline for Stockton. After Stockton, it more closely parallels CA 99 toward the state capital of Sacramento, although again, most of the cities and towns here are found along CA 99 instead of I-5. Several miles after I-5 passes by downtown Sacramento, it makes a 90° turn to due west, then upon reaching Woodland, turns back to the northwest again toward Dunnigan. It is near Dunnigan that I-5 spawns another spur to the Bay Area, this time its own “child” I-505; I-505 connects to I-80 at Vacaville, shortening the trip to the Bay Area from northern California and points north.
Never straying far from the Sacramento River valley, I-5 continues north past Red Bluff and Redding toward the mountains of the Shasta National Forest. The rest of the route in California, which passes the cities of Weed and Yreka, is much more mountainous and winding than it was further south. Three miles across the state line in Oregon, after a gradual climb in California, I-5 reaches its highest point: the 4,310-ft. (1,314 m) summit of Siskiyou Pass. The descent as one continues north, though, is anything but gradual: it is a seven-mile, 6% grade that is considered one of the most treacherous in the entire Interstate system, especially in winter. Motorists traveling this way in winter are advised that ALL vehicles, even passenger cars, are required to use tire chains or equivalent traction devices through Siskiyou Pass whenever the Oregon State Police deem their use necessary.
Most of the rest of southern Oregon is fairly mountainous, although I’m not aware of any particularly treacherous stretches after Siskiyou Summit. From Ashland to Central Point (just past Medford), I-5 actually turns northwest, and then it turns to the west until Grants Pass, turning once again to the north there. The terrain remains hilly to mountainous most of the way to Springfield, although less so the farther north I-5 goes; after Springfield, I-5 parallels the Willamette River valley and becomes remarkably flat and straight for a considerable distance. After the state capital of Salem, I-5 makes a slight northeastward turn toward the Portland metropolitan area, and passes through the tight pair of “Terwilliger Curves” just before spawning I-405 to serve downtown Portland. I-5 itself turns to the northeast and proceeds across the Willamette here, passing through eastern Portland for the remainder of its jaunt through Oregon.
Several miles north of Portland, I-5 crosses the Columbia River on the Interstate Bridge, a twin through-truss structure featuring one lift span that permits commercial shipping traffic to use the Columbia. Entering Washington state at this point, it largely parallels the east bank of the Columbia for about 40 miles (64 km) to Longview, then heads straight north through the Willapa Hills region and the city of Chehalis on its way to the Evergreen State’s capital of Olympia. From there, I-5 turns to the east-northeast, passing through the Fort Lewis military installation on its way toward Tacoma; as it passes through that city, the highway makes three fairly sharp turns — the first one to the north, a second one to the east near downtown, and a third one back to the north on the city’s east end.
From here, I-5 proceeds north toward Seattle; a portion of the highway actually runs beneath Seattle’s convention center, just outside the downtown area. Never straying far from the shore of Puget Sound, I-5 proceeds through Everett, Mt. Vernon, and Bellingham, turning to the northwest a bit after the latter. The northern end of I-5, just northwest of the town of Blaine, is inside the bi-national Peace Arch Park; this is the second-busiest U.S.-Canada border crossing, trailing only the Ambassador Bridge crossing at Detroit, MI and Windsor, Ontario. Immediately across the border in Surrey, B.C., I-5 transitions into British Columbia provincial highway 99, which connects to the major city of Vancouver a mere 30 miles (48 km) away.
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