Along this stretch, Heritage Road leads west to the Air Mobility Command Museum on the base grounds.

After the air base, the road continues north through a mix of farmland and woodland with some homes to the west of the Little Creek Wildlife Area.

The route comes to a junction with the eastern terminus of DE 8 as it leaves Little Creek and becomes Bayside Drive again.

At this point, the route turns northwest, with the name becoming Denny Street, and runs past homes and businesses, curving north to intersect the eastern terminus of DE 42.

The route turns west onto Taylors Bridge Road and crosses the marshy Blackbird Creek.

After this, the route turns north to remain on Silver Run Road and passes through areas of farms, woods, and wetlands in the Augustine Wildlife Area a short distance to the west of the Delaware River, coming to a bridge over Silver Run.

[3][4] Upon leaving Port Penn, DE 9 heads through marshland with some fields and woods within the Augustine Wildlife Area.

Within the oil refinery, the road crosses Norfolk Southern's Reybold Industrial Track railroad line at-grade.

At this point, the route turns to the northeast and passes between Ommelanden Park to the west and the Ommelanden Hunter Training Center to the east before running between residential subdivisions to the west and the northern training grounds for the Delaware National Guard to the east.

The road continues into marshland immediately to the northwest of the Delaware River, crossing Army Creek, before entering the city of New Castle.

The route turns north-northwest onto Washington Street and crosses Norfolk Southern's New Castle Secondary railroad line at-grade, heading into residential areas.

The route narrows back to two lanes and crosses the Jack A. Markell Trail, where the parallel multi-use trail ends, before it heads across the Norfolk Southern line again at-grade, at which point it turns east-northeast onto Ferry Cut Off Street near the New Castle Historic District.

[3][4] Here, DE 9 turns northeast onto East 6th Street, crossing a marshy creek and widening into a four-lane divided highway.

The road briefly becomes a divided highway again and intersects the southern terminus of DE 9A, which heads east to provide access to I-495 and the Port of Wilmington.

The one-way pair, which carries two lanes in each direction, passes rowhouses and businesses, with New Castle Avenue merging onto South Heald Street.

Here, US 13/DE 9 continue north-northeast on four-lane undivided South Heald Street, coming to an intersection with the northern terminus of DE 9A.

DE 9 continues northwest through residential and commercial areas as a four-lane undivided road, entering downtown Wilmington.

[12] In 1931, what would become DE 9 was upgraded to a state highway between Bay Road and Little Creek and between Port Penn and Delaware City.

[17] In 1956, New Castle Avenue was widened to a four-lane divided highway between Landers Lane and Rogers Corner.

[19] The current Reedy Point Bridge carrying DE 9 over the Chesapeake and Delaware Canal was completed in 1968.

[22] On October 27, 2008, construction began to convert the intersection at the southern terminus with DE 1 into an interchange, with Governor Ruth Ann Minner in attendance at the groundbreaking ceremony.

[4] On September 6, 2016, the U.S. Army Corps of Engineers began construction to demolish and replace the drawbridge carrying DE 9 over the Delaware City Channel with a fixed-span bridge.

[16] From January 6, 2023, to March 20, 2023, a roundabout will be constructed at the entrance to Fort DuPont north of the Reedy Point Bridge.

The official designation of the route runs 0.78 miles (1.26 km) along Terminal Avenue between DE 9 and the Port of Wilmington, interchanging with I-495.

Signage has the route continuing north along Christina Avenue to an intersection with US 13 and DE 9 for a total length of 2.0 mi (3.2 km).

[1][27] Christina Avenue originally became a state highway by 1924, serving as part of US 40 that connected to a ferry across the Delaware River to Penns Grove, New Jersey, in 1926.

In Tybouts Corner, the truck route turns northeast to join US 13 on four-lane divided South Dupont Highway.