State Route 86 (SR 86) is a north–south state highway in the U.S. State of California that connects the Imperial and Coachella valleys in the southeastern desert region of the state. It runs from State Route 111 near the Mexican border crossing at Calexico north through the Imperial Valley via El Centro and Brawley, and around the west side of the Salton Sea into the Coachella Valley. It then goes through Coachella before terminating at Interstate 10 in Indio.

SR 86 begins at an intersection with SR 111, just east of the town of Heber, as Heber Road. After traveling west through Heber, and intersecting CR S31, SR 86 heads north and enters the city of El Centro (as 4th Street), having an interchange with I-8. Passing through downtown El Centro, SR 86 intersects Main Street (CR S80) before curving to the west (as Adams Avenue). The highway continues north on Imperial Avenue before it enters the city of Imperial and passes Imperial County Airport, continuing north as it leaves the city limits.

North of Imperial, SR 86 intersects CR S27 before making a turn to the northeast, entering the city of Brawley. It passes to the west of downtown (as Western Avenue) before turning west onto Main Street, running concurrently with SR 78. Both SR 78 and 86 turn northwest before passing through the city of Westmoreland and intersecting CR S30. After briefly turning west, SR 78 and 86 turn northwest again and pass through Elmore and Kane Spring; SR 78 turns west (towards San Diego County), while SR 86 continues northwest along the western edge of the Salton Sea (just east of Anza-Borrego Desert State Park), before it intersects CR S22. SR 86 passes through the Torres-Martinez Indian Reservation and Coolidge Spring before entering Riverside County.

Just north of the county line in Oasis, SR 86 continues north on an expressway, turning away from the Salton Sea and heading through agricultural fields and farmlands. The route then meets SR 111, and turns northwest, running parallel to that highway. As it nears Indio, the expressway turns into a freeway. SR 86 ends at an interchange with I-10.

SR 86 is part of the California Freeway and Expressway System, and north of the southern SR 78 junction is part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration.

In the late 20th century, SR 86 had a rather notorious reputation for frequent and often fatal collisions. For much of its length, especially between the southern tip of the Coachella Valley to the Imperial County line, SR 86 was a two-lane road with easy access from rural side roads. A driver trying to pass might find himself headed straight for the side of another vehicle pulling out from one of the side roads. This reputation earned SR 86 the nickname "Blood Alley".

Originally a part of U.S. Route 99 until the 1960s, the northern end of SR 86 was widened and rerouted through the new and rather unusually numbered "86S Expressway" (for “supplemental”) soon after the signing of the North American Free Trade Agreement (NAFTA), making SR 86 a four- or six-lane highway for most of its length. Since it is easier to enter California from the Imperial Valley than through San Diego, SR 86 sees a great deal of truck traffic to and from Mexico, earning it still another nickname, "The NAFTA Highway". The new highway has proven to be at least as dangerous as the old alignment owing to much the same problems of poorly marked and uncontrolled side roads. A rash of fatal crashes in early 2005 prompted the city of Coachella to push Caltrans for the installation of at least two more traffic signals on SR 86S.

State Route 86S
Location	Coachella
Existed	1964–2012

State Route 86S (SR 86S) was an expressway running through the Coachella Valley. In December 2012, the SR 86 designation was transferred to the routing of SR 86S, and SR 86S ceased to exist. State Route 195 was removed from the state highway system as a result. SR 86 was originally truncated to Avenue 46, but the State Route 86S expressway, which replaced SR 86 around the east side of Coachella and Indio, did reach I-10. Despite SR 86's rerouting, the Airport Boulevard interchange remains numbered as exit 13, reflecting the former SR 86S's distance.

Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage. R reflects a realignment in the route since then, M indicates a second realignment, L refers to an overlap due to a correction or change, and T indicates postmiles classified as temporary (for a full list of prefixes, see California postmile § Official postmile definitions). Segments that remain unconstructed or have been relinquished to local control may be omitted. The numbers reset at county lines; the start and end postmiles in each county are given in the county column.

County	Location	Postmile	Destinations	Notes
Imperial IMP R0.00-67.82	​	R0.00	Heber Road	Continuation beyond SR 111
	Heber	R0.00	SR 111 – Brawley, Calexico
		2.08	CR S31 (Dogwood Road)
	El Centro	6.01	I-8 – Yuma, San Diego	Interchange; south end of I-8 Bus. overlap; I-8 exit 115
		L7.31	CR S80 east (Main Street) – Holtville	South end of CR S80 overlap; CR S80 is former US 80
		L8.53 7.31	I-8 BL west (Imperial Avenue) / CR S80 west (Adams Avenue) to I-8 – San Diego	North end of CR S80 / I-8 Bus. overlap; CR S80 is former US 80
	Imperial	10.82	CR S28 (Barioni Boulevard)
	​	15.32	CR S27 (Keystone Road)
	Brawley	20.63	Main Street, 1st Street – Blythe	Former SR 78 east
	​	​	SR 78 east / Fredricks Road	South end of SR 78 overlap
	Westmorland	​	CR S26 east (Boarts Road)	Western terminus of CR S26
		27.51	CR S30 (Center Street)
	​	43.56	SR 78 west – Julian, Oceanside	North end of SR 78 overlap
	Salton City	56.12	CR S22 west (Borrego-Salton Seaway) / South Marina Drive – Borrego Springs, Anza-Borrego, Park Headquarters	Eastern terminus of CR S22
	​	63.63	Brawley Avenue – Salton Sea Beach
	Desert Shores	66.14	Desert Shores Drive
Riverside RIV 0.00-R23.00	​	R12.48	66th Avenue to SR 111 – Niland, Calipatria, Mecca
	​	​	62nd Avenue
	Coachella	R16.74	Airport Boulevard	Interchange; signed as exit 16
		​	52nd Avenue
		​	50th Avenue, Tyler Street
		​	South end of freeway
	Coachella–Indio line	R22.16	Dillon Road (I-10 Bus.) to I-10 east	Interchange
	Indio	R23.00	I-10 west – Los Angeles	Northbound exit and southbound entrance; I-10 exit 145 eastbound, 146 westbound
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus

• California Roads portal

• Caltrans: State Route 86 highway conditions
• Caltrans Traffic Conditions Map
• California Highway Patrol Traffic Incidents
• California @ AARoads.com - State Route 86
• California Highways: SR 86