California
Nevada (PART 1/PART 2)
Utah
Wyoming
Nebraska
Iowa (PART 1/PART 2/PART 3)
Illinois/Indiana
Ohio
Pennsylvania
New Jersey
I-80 had five branches, the most of any interstate. However, they have all been renumbered after suffixes were forbidden on interstates (except for I-35 in Texas and Minnesota). There were three branches called I-80N (the most noticeable of which linked Portland, OR to Salt Lake City), and two branches called I-80S (both of which became separate sections of I-76 between Denver and Philadelphia).
I-480 was the number for the Embarcadero Freeway in San Francisco. It was hated by San Franciscans because they felt it had destroyed their city. After suffering damage in the 1989 Loma Prieta earthquake, the double-decker freeway was completely demolished, opening the waterfront area to further development.
I-880, a double-decker freeway in Oakland, CA, also suffered heavy damage in the earthquake that rocked the Bay Area in 1989. In subsequent years, it was rebuilt on a new alignment with the decks carrying its northbound and southbound lanes being built at the same level. The double-decker freeway no longer exists.
I-880 was previously used for what is now I-80 around Sacramento, CA. The original I-80's alignment, which runs through the city, is currently the Business I-80/US 50/Secret I-305 freeway.
I-180 in Cheyenne, WY, is an interstate that has traffic lights.
Between Chicago and Cleveland, I-80 is multiplexed with another interstate.