Most of the Passaic County section was part of the Bergen-Passaic Expressway, a road planned in the 1940s but not completed until the 1960s to alleviate congestion on US 1/9/46 and NJ 4 as approaches to the George Washington Bridge. Specifically, the Bergen-Passaic Expressway was designed to pull Paterson-bound traffic off NJ 4. When the road was added to the Interstate highway system, it became part of a greater conduit from the west; however, the last sections of I-80 west of Paterson were not completed until the 1970s.
A little-remembered fact is that I-80 occupies the old right-of-way of the Lackawanna Railroad main line going around the base of Garret Mountain in Paterson and Woodland Park, and overlays it for a bit in Totowa as well. The Lackawanna bridge abutments at the Passaic River are still visible from McBride Avenue in Woodland Park and Riverview Drive in Totowa.
Contrary to popular belief, I-80 does not go to New York, even though New York is given as a control city on eastbound signs throughout New Jersey and even near Youngstown, Ohio (but not, curiously, in Pennsylvania). Prior to the completion of I-95 in the Ridgefield Park area, the entire Bergen-Passaic Expressway was signed I-80; today, the road's eastern terminus is at the New Jersey Turnpike in Teaneck.
Only the 7.57-mile portion of the freeway in Passaic County is included here; the mile markers are from the highway’s New Jersey origin at the Delaware River.
| Mile | Street Name | Feature (West to East) |
| 52.87 | Entering Wayne Twp, Passaic Co. | |
| 52.87 | I-80 | Passaic River {bridge} |
| 52.89 | I-80 | Fairfield Rd, CR 679 {bridge} |
| 53.33 | I-80 | Singac Brook {bridge} |
| 53.54 | I-80 | Lackawanna Railroad {underpass} |
| 53.62 | Bergen-Passaic Expwy | NJ 23 southbound {underpass} |
| 53.75 | Bergen-Passaic Expwy | NJ 23 northbound, Interchange 53 {underpass} |
| 54.10 | Entering Totowa Boro | |
| 54.24 | Bergen-Passaic Expwy | Unnamed stream {pipe} |
| 54.40 | Bergen-Passaic Expwy | Riverview Dr, CR 640 {overpass} |
| 54.54 | Bergen-Passaic Expwy | Lackawanna Railroad {overpass} |
| 54.73 | Bergen-Passaic Expwy | Minnisink Rd, CR 642, Interchange 54 {underpass} |
| 54.88 | Bergen-Passaic Expwy | Unnamed stream {pipe} |
| 55.21 | Bergen-Passaic Expwy | Union Blvd, NJ 62 | CR 646, Interchange 55 {underpass} |
| 56.29 | Bergen-Passaic Expwy | Riverview Dr, CR 640 {bridge} |
| 56.34 | Bergen-Passaic Expwy | Passaic River {bridge} |
| 56.34 | Entering Woodland Park Boro | |
| 56.43 | Bergen-Passaic Expwy | McBride Ave, CR 639 {bridge} |
| 56.54 | Bergen-Passaic Expwy | Unnamed stream {pipe} |
| 56.84 | Bergen-Passaic Expwy | Pedestrian crossing {underpass} |
| 57.07 | Bergen-Passaic Expwy | Squirrelwood Rd, CR 636, Interchange 56 {underpass} |
| 57.25 | Bergen-Passaic Expwy | Unnamed stream {pipe} |
| 57.35 | Entering Paterson City | |
| 57.66 | Bergen-Passaic Expwy | New St, CR 633 {underpass} |
| 58.22 | Bergen-Passaic Expwy | NJ 19, Interchange 57 {overpass} |
| 58.36 | Bergen-Passaic Expwy | Marshall St {overpass} |
| 58.37 | Bergen-Passaic Expwy | Main St, CR 509 {overpass} |
| 58.50 | Bergen-Passaic Expwy | Elm St {overpass} |
| 58.55 | Bergen-Passaic Expwy | 21 St {overpass} |
| 58.55 | Bergen-Passaic Expwy | Spring St, CR 647 {overpass} |
| 58.67 | Bergen-Passaic Expwy | Erie Railroad {overpass} |
| 58.87 | Bergen-Passaic Expwy | Beckwith Ave {overpass} |
| 59.06 | Bergen-Passaic Expwy | Madison Ave, CR 649, Interchange 58 {underpass} |
| 59.38 | Bergen-Passaic Expwy | Pedestrian crossing {underpass} |
| 59.69 | Bergen-Passaic Expwy | Trenton Ave {underpass} |
| 60.04 | Bergen-Passaic Expwy | Lakeview Ave, CR 624, Interchange 59 {underpass} |
| 60.27 | Bergen-Passaic Expwy | Ramps to NJ 20 {overpass} |
| 60.41 | Bergen-Passaic Expwy | NJ 20, Interchange 60 {overpass} |
| 60.44 | Bergen-Passaic Expwy | Passaic River {bridge} |
| 60.44 | Entering Elmwood Park Boro, Bergen Co. | |