Interstate 19 (I-19): Nogales to Tucson in Kilometers, With Safety Data

How long is I-19?

FHWA's Route Log gives I-19 63.37 miles, all of them in Arizona. Wikipedia lists 63.43 miles (102.08 km), Interstate Guide prints 63.35, and ADOT calls the highway 102 kilometers long. The three mile figures are within a tenth of a mile of each other.

The Route Log shows no pavement shared with another Interstate. Exit numbers and distance signs are in metric units, so the exit numbers climb past 100 near Tucson even though the road is only about 63 miles long.

Where I-19 starts and ends

The southern end is in Nogales, at the junction with Business Loop 19 (Grand Avenue) and Crawford Street. That spot is kilometer post 0, about 300 feet from the Mexican border. The freeway curves around Crawford Hill and bypasses downtown Nogales, and drivers who keep going south reach Heroica Nogales, Sonora, on surface streets.

The northern end is the Crossing, the I-10 interchange in Tucson at I-10 exit 260. On the way north, I-19 passes Rio Rico, Tumacacori-Carmen, Tubac, Amado, Green Valley and Sahuarita, then crosses the San Xavier Indian Reservation. It follows the Santa Cruz River north from Rio Rico and crosses the river only once, just before Tucson.

Exit 29 serves Tumacacori National Historical Park, exit 92 Mission San Xavier del Bac and exit 95, Valencia Road, Tucson International Airport. At exit 4, State Route 189 (Mariposa Road) lets trucks skirt Nogales on their way to the Nogales-Mariposa Port of Entry, the main freight crossing. Mexico's Federal Highway 15 connects there and runs on to Mexico City.

Interstate junctions along I-19

Reading south to north, the list has a single entry: I-10 at the Tucson end. I-19 meets it in two steps. Exit 101 handles I-10 east toward El Paso, and the freeway ends at the ramps for I-10 west toward Phoenix. The larger interchanges farther south, SR 189 at exit 4, SR 289 (Ruby Road) at exit 12 and SR 86 (Ajo Way) at exit 99, carry Arizona state routes, which the list leaves out. I-11 has no Arizona mileage in the Route Log, so it does not appear either.

Fatal crashes on I-19

FARS records 29 fatal crashes on I-19 from 2020 to 2024, and they killed 34 people, close to 7 a year. At 63.37 miles, I-19 falls under the 100-mile minimum for the death rate ranking of 56 Interstates, so no rate is shown for it here.

Pima County, at the Tucson end, had 19 of the deaths. Santa Cruz County, at the border end, had the other 15. The yearly count went from 9 in 2020 to 8 in 2021 and 7 in 2022, fell to 2 in 2023 and came back to 8 in 2024. With totals this small, one or two crashes can move a year up or down by several deaths.

Counties with the most I-19 crash deaths

Bridges on I-19

Counting only bridges that carry the main line, the 2025 National Bridge Inventory has 142 on I-19. Not one rates Poor: 106 rate Good and 36 rate Fair. The median bridge was built in 1969.

Some of the newer structures are at the north end, where the Crossing project added ten bridges and eight ramps when it rebuilt the I-10 interchange between June 2002 and August 2004. The road's one bridge over the Santa Cruz River sits on the San Xavier Indian Reservation just south of Tucson.

Tolls on I-19

I-19 has no entry in FHWA's toll inventory for January 1, 2023, and the Wikipedia and Interstate Guide articles describe no tolled lanes opened since. Nogales to Tucson costs nothing in tolls.

Older ADOT planning documents cited by Wikipedia called for three lanes each way from Irvington Road to Valencia Road and up to five lanes each way between I-10 and San Xavier Road by 2030; we found no current ADOT schedule for either. Neither plan is described as a toll project.

US 89, a metric pilot and the fight over the signs

I-19 joined the Interstate numbering plan on August 14, 1957, and replaced US 89 between Nogales and Tucson. Wikipedia dates the first open piece, a 3-mile stub from I-10 to Valencia Road, to 1962. Tucson to Helmet Peak Road was finished on February 12, 1972, Rio Rico to Nogales in 1974 and Green Valley to Rio Rico in 1978, the year an ADOT report listed the project complete. Interstate Guide places the last link, Tubac to Chavez Siding Road (exit 40), in 1979. AASHTO approved dropping US 89 south of Flagstaff on June 15, 1992.

ADOT connects the kilometer signs to the Metric Conversion Act of 1975, which made metric the preferred system without requiring anyone to use it. I-19 was nearing completion and became a pilot. Interstate Guide calls it a Carter administration project that also served Mexican visitors traveling to Tucson and Phoenix. The sign contract, signed on January 17, 1980, paid for metric signs, kilometer posts and bilingual signs at some locations. Two contracts in 1999 replaced signs along the whole route.

Customary-unit signs went up between exits 99 and 101 in 2004, after the Crossing was rebuilt. In 2009 or 2010 ADOT proposed moving the rest of the road to mileposts and dropped the idea after communities and businesses along I-19 objected. In May 2025 USDOT spokesperson Nate Sizemore told The Wall Street Journal the department wanted to "restore American standards" on the road. KGUN reported at the time that ADOT had heard nothing from its federal partners and that no timeline or formal proposal had been released. We found no formal federal proposal announced as of November 2026. Randy Graf of the Green Valley Chamber of Commerce told the station that businesses listing exit numbers in their marketing would face costs.

The $54.3 million Crossing project swapped the old trumpet interchange with I-10 for a three-level interchange slightly to the west, dedicated on August 7, 2004. A $54 million project then rebuilt the Ajo Way (SR 86) interchange as a single-point urban interchange between March 2016 and March 2018, and a $32 million second phase, finished in spring 2020, built braided ramps between Irvington Road and Ajo Way. The FAST Act designated I-11 in Arizona along a corridor that generally follows I-19 from Nogales to Tucson.

I-19 traffic and road conditions

Arizona's 511 service covers every kilometer of I-19, from the border at Nogales to the Crossing in Tucson. Open the link below to see today's crashes and lane closures; the death counts on this page run only through 2024.

I-19 questions