Nevada State Routes

Interstate 580 (I-580) is an Interstate Highway in northwestern Nevada. It runs concurrently with U.S. Highway 395 (US 395) from Interstate 80 in Reno, to the east leg of US 50 in Carson City. Although the freeway has existed in Reno with the I-580 designation since the 1960s, the interstate was signed only as US 395 until the portion between Reno and Carson City was completed in 2012. I-580 is not complete; the highway is expected to be signed between the east and west legs of US 50 in Carson City, however the final phase of freeway construction between Fairview Drive and US 50 west has been postponed several times with an uncertain completion date.

I-580 is still under development. The freeway exists today from I-80 near downtown Reno south to Fairview Drive in Carson City. Eventually, the highway will continue in a southerly direction from Fairview Drive to terminate at the junction of US 395 and US 50 just south of Carson City. Fairview Drive is being temporarily used as a connector to Carson Street and US 395.

The constructed portion begins at Fairview Drive along the eastern edge of Eagle Valley, where most of the population of Carson City lives. The highway loosely follows the former alignments of Edmonds Drive and Lompa Lane along the eastern half of the city, which were relocated or truncated to make room for the freeway.

After rejoining the original alignment of US 395 near the Carson–Tahoe Hospital the highway crests Lakeview Hill to enter the Washoe Valley. The portion of I-580 through Washoe Valley is prone to high crosswinds, and the freeway is frequently closed to high-profile vehicles. During prohibited times, trucks are re-routed to U.S. Route 395 Alternate, which is the old routing of US 395. The high wind area ends near the Bowers Mansion interchange near the northern end of the Washoe Valley.

Unlike the old US 395 which ran along the valley floor of Pleasant Valley, I-580 is routed in the mountains overlooking the valley. While traversing Pleasant Valley, the highway crosses the Galena Creek Bridge, the largest cathedral arch bridge in the world. Upon the descent from these mountains the highway cuts through the center of one of the largest geothermal power plants in the United States, Ormat Industries' Nevada Power station, just before entering Reno.

At the extreme southern edge of Reno the highway has a junction with the Mount Rose Highway (SR 431) and Geiger Grade (SR 341), which connect the freeway with North Lake Tahoe and Virginia City, respectively. Upon entering Reno, the freeway proceeds in a generally northern direction, crossing Virginia Street, the old routing of US 395, several times. Along the way the freeway passes to the side of the The Summit Sierra Mall, Meadowood Mall and Reno–Tahoe International Airport. The I-580 designation ends at the Reno Spaghetti Bowl where the highway crosses I-80; however, the freeway continues on only as US 395, heading towards the north valley neighborhoods of Sun Valley, Lemon Valley and Stead before eventually crossing the California state line.

Development of the I-580 / US 395 freeway has been in planning since 1957, but significant construction did not occur until over a decade later. Below is a timeline of the opening dates of the current freeway segments that are or will be part of I-580.

The remaining portion of I-580 that is not complete is what the Nevada Department of Transportation has internally designated as phase 2B of the Carson City Freeway. Phase 2B will complete the remaining freeway to US 50 west, including the interchange with US 395 and South Carson Street. Construction of Phase 2A finished in September 2009; however, construction of Phase 2B may not be completed until as late as 2014 due to funding problems with the state legislature.

For other exits on US 395, see U.S. Route 395 in Nevada.