From this point, the four-lane freeway heads south along the east bank of the river through the Delaware Water Gap, immediately reaching a westbound exit and eastbound entrance for Old Mine Road.

[4][6] Now maintained by the New Jersey Department of Transportation, the road makes a sharp turn to the east and comes to a u-turn ramp in both directions that also has access to the Appalachian Trail.

[4] The highway heads south again and enters Knowlton Township, where it comes to another set of U-turn ramps that also includes a weigh station in the eastbound direction.

After turning southeast and passing near suburban business parks, the highway crosses over the NJ Transit's Morristown Line/Montclair-Boonton Line and reaches a partial interchange with US 46,[4][6] which has only a westbound exit and eastbound entrance.

[4][7][8] After this, the road heads farther north of the railroad tracks and briefly passes through Jefferson and Rockaway townships before continuing into Wharton.

[4] The highway makes a turn east as it comes into an area of business parks, with the median widening before an interchange serving US 202 and Cherry Hill Road (CR 654).

[4] From this point, I-80 continues east through wooded areas as a six-lane freeway, crossing into Montville,[4][6] where there is a partial interchange providing access to Hook Mountain Road.

At this point, the freeway widens to eight lanes and continues into Totowa, passing near more commercial areas and over the Norfolk Southern Railway railroad line as it comes to an interchange with Minnisink Road (CR 642) that has access to and from the west.

[4] I-80 crosses the Passaic River a third time and enters Woodland Park, where it turns to the northeast past suburban neighborhoods and reaches an interchange serving Squirrelwood Road (CR 636).

[4][6] Passing to the north of the Garret Mountain Reservation, the freeway enters Paterson and turns east into urban areas as it comes to the interchange with Route 19.

After Route 19, I-80 runs above Paterson on a viaduct, crossing over the NJ Transit's Main Line before coming to the exit for Madison Avenue (CR 649).

The road returns to ground level near urban neighborhoods as it comes to an eastbound exit and westbound entrance serving Market Street before reaching an interchange with Route 20.

[4] It continues near suburban neighborhoods, coming to a bridge over the New York, Susquehanna and Western Railway's New Jersey Subdivision line, and passes over the NJ Transit's Bergen County Line as it comes to an interchange with the Garden State Parkway on the border of Elmwood Park and Saddle Brook that also has connections to Midland Avenue (CR 67).

The freeway passes over the New York, Susquehanna and Western Railway line again and turns south along the west bank of the Saddle River, eventually crossing it into Lodi.

Past Route 17, I-80 gains a 3-2-2-3 local–express lane configuration and crosses over the NJ Transit's Pascack Valley Line before passing through industrial parks and runs briefly through South Hackensack.

[6] A freeway along the I-80 corridor was first planned in 1936 as a replacement for the cross-state US 46, running from the George Washington Bridge west to the Delaware Water Gap and Scranton, Pennsylvania.

[26] In 1994, the New Jersey Department of Transportation adopted and began using the Rockfall Hazard Rating System for evaluating and ranking highway rock-cut slopes.

In June 2019, the New Jersey Department of Transportation held a public meeting regarding a proposed rock wall along I-80 in the Delaware Water Gap National Recreation Area.

[29] A temporary bridge had to be built, and traffic on this part of I-80 as well as adjacent roads was snarled; in addition, a state of emergency had been declared for Morris County.

[32] In August 2012, the New Jersey Department of Transportation announced a $73-million (equivalent to $95.8 million in 2023[25]) project will completely rehabilitate and improve I-80 eastbound between US 202 and the South Beverwyck Road interchange, a very busy part of highway with an average of 159,000 vehicles traveling it daily.

I-80 east is set to remain closed until further notice, and repair work has been made more challenging due to the mine and incoming weather conditions.