Editing Interstate 8 (section)

{{Short description|Interstate Highway in California and Arizona}}
{{Other uses|I8 (disambiguation)}}
{{Use American English|date=April 2025}}
{{Use mdy dates|date=May 2023}}
{{featured article}}
{{Infobox road
| country = USA
| type = I
| route = 8
| maint = [[Caltrans]] and [[Arizona Department of Transportation|ADOT]]
| length_mi = 350.34
| length_notes = {{convert|171.98|mi|km}} in California<ref name=calnexus/><br />{{convert|178.36|mi|km}} in Arizona<ref name="ADOT Highway Log"/>
| established = 1964
| map = {{maplink-road|from=Interstate 8.map}}
| map_custom = yes
| map_notes = I-8 highlighted in red
| direction_a = West
| terminus_a = Sunset Cliffs Boulevard&nbsp;/ Nimitz Boulevard in [[San Diego|San Diego, CA]]
| junction = {{Plainlist|<!-- Major junctions only; Only up to ten most major intersections and cities belong here; please read [[WP:USRD/STDS]] for more info -->
*{{Jct|state=CA|I|5}} in San Diego, CA
*{{Jct|state=CA|I|805}} in San Diego, CA
*{{Jct|state=CA|I|15|SR|15}} in San Diego, CA
*{{Jct|state=CA|SR|111}} in [[El Centro, California|El Centro, CA]]
*{{Jct|state=CA|SR|7}} near [[Holtville, California|Holtville, CA]]
*{{Jct|state=AZ|US|95}} in [[Yuma, Arizona|Yuma, AZ]]
*{{Jct|state=AZ|SR|85}} in [[Gila Bend, Arizona|Gila Bend, AZ]]
}}
| direction_b = East
| terminus_b = {{Jct|state=AZ|I|10}} in [[Casa Grande, Arizona|Casa Grande, AZ]]
| states = [[California]], [[Arizona]]
| counties = '''CA:''' [[San Diego County, California|San Diego]], [[Imperial County, California|Imperial]]<br />'''AZ:''' [[Yuma County, Arizona|Yuma]], [[Maricopa County, Arizona|Maricopa]], [[Pinal County, Arizona|Pinal]]
| system1 = {{infobox road/browselinks/USA|state=CA}}
| system2 = {{infobox road/browselinks/USA|state=AZ}}
| browse = {{ca browse|previous_type=CA|previous_route=7|route=CA|next_type=CA|next_route=9}}{{az browse|previous_type=AZ|previous_route=989|route=AZ|next_type=I|next_route=10}}
}}

[[File:San Diego Trolley over Interstate 8.jpg|thumb|right|300px|I-8 in [[San Diego]], from the [[San Diego Trolley]]]]
'''Interstate&nbsp;8''' ('''I-8''') is an [[Interstate Highway System|Interstate Highway]] in the [[southwestern United States]]. It runs from the southern edge of [[Mission Bay (San Diego)|Mission Bay]] at Sunset Cliffs Boulevard in [[San Diego|San Diego, California]], almost at the Pacific Ocean, to the junction with [[Interstate 10 in Arizona|I-10]], just southeast of [[Casa Grande, Arizona]]. In California, the freeway travels through the San Diego metropolitan area as the '''Ocean Beach Freeway''' and the '''Mission Valley Freeway''' before traversing the [[Cuyamaca Mountains]] and providing access through the [[Imperial Valley]], including the city of [[El Centro, California|El Centro]]. Crossing the [[Colorado River]] into [[Arizona]], I-8 continues through the city of [[Yuma, Arizona|Yuma]] across the [[Sonoran Desert]] to Casa Grande, in between the cities of [[Phoenix, Arizona|Phoenix]] and [[Tucson, Arizona|Tucson]].

The first route over the Cuyamaca Mountains was dedicated in 1912, and a [[plank road]] served as the first road across the Imperial Valley to Yuma; east of there, the [[Gila Trail]] continued east to [[Gila Bend, Arizona|Gila Bend]]. These were later replaced by [[U.S. Route&nbsp;80]] (US&nbsp;80) across California and part of Arizona, and [[Arizona State Route&nbsp;84]] (SR&nbsp;84) between Gila Bend and Casa Grande. The US&nbsp;80 freeway through San Diego was largely complete by the time it was renumbered as I-8 in the [[1964 state highway renumbering (California)|1964 state highway renumbering]]; east of San Diego, the US&nbsp;80 roadway was slowly replaced by I-8 as construction progressed in the Imperial Valley. The Arizona portion of the road was built starting in the 1960s. Several controversies erupted during the construction process; questionable labor practices in Imperial County led to the federal conviction of mobster [[Jimmy Fratianno]], and a [[U.S. House of Representatives]] subcommittee found that the Arizona government had mismanaged financial resources.

The route was completed in 1975 through California, and by 1977 through Arizona, though the bridge over the Colorado River was not completed until 1978. Since then, the freeway through San Diego has been widened due to increasing congestion, and another portion in Imperial County had to be rebuilt following damage by the remnants of [[Hurricane Kathleen]].