Interstate 17

Interstate 17
The Sunset Point Rest Area along Interstate 17 overlooks the Black Canyon above Sunset Point, northeast of Sheep Gulch and east of the Bradshaw Mountains. 04/26/17

I-17 is one of the three north to south Interstate highways in Arizona, and one of the two Interstate highways to never leave the state. The freeway connects the low desert of Phoenix and the Vally of the Sun with the high mountains of Flagstaff, providing a relatively quick route between the two cities.

Interstate 17 Guides

North

South

The history of Interstate 17 is tied into the route it replaced - Arizona State Route 69. In the 1930s, traffic planners realized the need for a faster route between Phoenix and Prescott. At the time, traffic had to take U.S. 89, which was somewhat out of the way.

A new route ascending through Black Canyon, designated State Route 69, was added to the state highway system in 1936 and appearing on maps in 1938. The road was completed by 1940 to Prescott, and paved progressively up to Prescott.

In the 1950s, a new route was needed to Flagstaff, as U.S. 89A was restricted due to the grade out of Oak Creek Canyon. This was designated in 1954, and numbered Arizona State Route 79 (recycling the original number from the road through Oak Creek Canyon).

A route was subsequently designated from Phoenix to Flagstaff as part of the Interstate Highway system. This route became Interstate 17.

Interstate 17 begins near Sky Harbor International Airport (PHX) at I-10/U.S. 60. Traveling west and north around Downtown Phoenix, I-17 forms the west and south legs of the "inner loop". Meeting Interstate 10 again along the Black Canyon Freeway at the Stack interchange, I-17 continues north roughly along 25th Avenue, transitioning to an alignment along 27th Avenue at Dunlap Avenue. Advancing further north, the freeway converges with Loop 101 (Agua Fria Freeway / Pima Freeway) and SR 74 as it continues toward the suburb of Anthem.

Beyond Anthem, Interstate 17 finally leaves the Phoenix Metropolitan Area, reaching the towns of New River and Black Canyon City before leaving the low desert and climbing quickly by the ghost town of Bumble Bee to Black Mesa. At the edge of the mesa is the Sunset Point rest area. The freeway stays fairly level at around 3,500 feet elevation until passing Cordes Junction, where SR 69 branches off.

Advancing from Cordes Junction, Interstate 17 travels north and drops down into the Verde Valley to reach the town of Camp Verde. Leaving Camp Verde, Interstate 17 passes the road to Montezuma Castle National Monument and Montezuma Well National Monument, before meeting SR 179 to Sedona.

Passing SR 179, Interstate 17 starts climbing again in earnest to reach 6,500 feet in elevation at Munds Park. After passing Flagstaff Airport, I-17 connects with Interstate 40 alongside SR 89A in south Flagstaff.

I-17 between I-10 (24th Street) and the Durango Curve (22nd Avenue) was originally part of Interstate 10. This section of freeway was incorporated into Interstate 17 when I-10 was realigned.

From Cordes Junction to Flagstaff, significant portions of Interstate 17 were originally constructed as a two lane freeway, with the other two lanes added later. The entire freeway was completed by 1978.

The mileposts on Interstate 17 begin at Milepost 194. I-17's mileposts are derived from State Route 69, which began at mile 201 of U.S. 89 originally, which is where the Grand Avenue overpass along Interstate 17 is today. Since Interstate 19's mileposts also correspond to U.S. 89's milepost system, it led to some speculation that I-17 and I-19 were supposed to be one freeway. However this was never in state highway system plans.

Construction History

Years noted are dates that the sections opened. In the case of the freeway north of Thomas Road, this is when SR 69 was turned into a limited access freeway.

The section from Miles 293-340 was constructed as State Route 79, and converted to a limited access highway before completion. The majority of this section (miles 298-337) was constructed as a two lane limited access freeway. Dates are included for when the additional lanes were added to the freeway.

Business Loops

The lone business route from I-17 was the decommissioned loop that followed former SR 69 through Black Canyon City.

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Page Updated Monday April 25, 2022.