Cisanggarung River is the western border of Central Java, from which Route 1 goes southeastward into Brebes Regency, adjacent with Northern railway line.
In Brebes section of Route 1, there are many salty egg sellers, as it becomes Brebes' main product.
4.5 km later, it turns eastwards, and reaches Downtown Brebes 22 km later.
There, Route 1 is divided.
The eastbound section follows Jl.
Ahmad Yani, and the westbound section follows Jl.
Jenderal Sudirman, where it passes by Brebes Station.
Jl.
Ahmad Yani then merges with Jl.
Jend.
Sudirman, and proceeds eastward as Jl.
Gajah Mada.

Continuing 2.5 km east, Route 1 enters Tegal City after crossing over Gangsa River.
The route then runs for three kilometer eastwards.
After encountering a junction near Pramesthi Hotel, Route 1 turns northward, carried by Jl.
Gajah Mada (1 km) and then Jl.
MT.
Haryono (500 m).
The junction also becomes the beginning point of Route 6 leading for Slawi, the seat of Tegal Regency.
After a junction near Port of Tegal, Route 1 goes eastward as Jl.
Yos Sudarso and Jl.
Martoloyo for two kilometers.

Upon crossing over Ketiwon River, Route 1 goes into Tegal Regency.
The route runs parallel with Northern railway line in the south and coastline of Java Sea in the north.
Before reaching Pemalang Regency, it travels eastward for 23 km, passes over the subdistricts of Kramat, Suradadi, and Warureja.

A bridge over Plawangan River marks the entrance of Route 1 into Pemalang.
Route 1 moves eastward for one kilometer, and then it turns southeastward for 1.5 km.
Route 1 follows Pemalang Ring Road after Pagaran Junction.
It initially runs for six kilometers eastwards, and then curves southward.
Route 1 turns eastward 780 m later after Gandulan Junction, in where Jl.
Perintis Kemerdekaan coming from Downtown Pemalang merges.
Route 1 then goes twelve kilometers eastwards until a bend in Comal.
It then curves northeastward for three kilometers, followed by another curving southeastward.

Route 1 enters Pekalongan Regency some 450 m later after crossing Sepait River.
The route runs eastward, where it passes through the subdistricts of Siwalan, Wiradesa, and Tirto.
It leaves Pekalongan Regency 5.5 km later when crossing Meduri River, and then enters Pekalongan City.
In this segment, Route 1 is carried by Jl.
Gajah Mada for two kilometers, when it is divided into two sections in front of Pekalongan Station.
The eastbound sections follows Jl.
Merdeka for 480 m. After crossing with Jl.
Imam Bonjol and Jl.
Patriot, it turns southward as Jl.
Pemuda, while the westbound section still follows Jl.
Gajah Mada.
The two sections meet in front of Muhammadiyah College of Economics, where it continues southward as Jl.
KH.
Mas Mansyur, and has level crossing with Northern railway line.
One kilometer later, it encounters Ponolawen Junction, where Route 1 turns eastward as Jl.
Jend.
Sudirman, Jl.
Setiabudi, and then Jl.
Sutomo.
Ponolawen Junction also becomes an access to Kajen, the seat of Pekalongan Regency.

After entering Batang Regency 4.5 km later, it goes into the downtown.
Continuing 3.3 km east, it makes a curving to the northeast.
When passing Sambong Bridge 550 m later, it begins to enter a mountainous region that becomes a continuation of Dieng Plateau located in the south.
Route 1 winds through the subdistricts of Kandeman, Tulis, Subah, Banyuputih, and Gringsing, in which there are many warungs and restaurants founded to cater all long-distance travellers.
Continuing 32 km east, it encounters a three-way junction in Surodadi Village, where Route 1 goes eastward, while most traffic in North Coast of Java takes the newer road diverging from here.
470 m later, the old Great Post Road diverges from Route 1.
All heavy vehicles aren't permitted to pass through Route 1 in this section considering its sharp climbs; instead they are obliged to take the curvaceous Great Post Road that passes through Alasroban Jungle.
Route 1 and Great Post Road meets again 1.5 km northeastward.
Route 1 then runs northeast for 360 m, and the mountainous segment before Semarang ends here.
After encount
Cisanggarung River is the western border of Central Java, from which Route 1 goes southeastward into Brebes Regency, adjacent with Northern railway line. In Brebes section of Route 1, there are many salty egg sellers, as it becomes Brebes' main product. 4.5 km later, it turns eastwards, and reaches Downtown Brebes 22 km later. There, Route 1 is divided. The eastbound section follows Jl. Ahmad Yani, and the westbound section follows Jl. Jenderal Sudirman, where it passes by Brebes Station. Jl. Ahmad Yani then merges with Jl. Jend. Sudirman, and proceeds eastward as Jl. Gajah Mada.
Continuing 2.5 km east, Route 1 enters Tegal City after crossing over Gangsa River. The route then runs for three kilometer eastwards. After encountering a junction near Pramesthi Hotel, Route 1 turns northward, carried by Jl. Gajah Mada (1 km) and then Jl. MT. Haryono (500 m). The junction also becomes the beginning point of Route 6 leading for Slawi, the seat of Tegal Regency. After a junction near Port of Tegal, Route 1 goes eastward as Jl. Yos Sudarso and Jl. Martoloyo for two kilometers.
Upon crossing over Ketiwon River, Route 1 goes into Tegal Regency. The route runs parallel with Northern railway line in the south and coastline of Java Sea in the north. Before reaching Pemalang Regency, it travels eastward for 23 km, passes over the subdistricts of Kramat, Suradadi, and Warureja.
A bridge over Plawangan River marks the entrance of Route 1 into Pemalang. Route 1 moves eastward for one kilometer, and then it turns southeastward for 1.5 km. Route 1 follows Pemalang Ring Road after Pagaran Junction. It initially runs for six kilometers eastwards, and then curves southward. Route 1 turns eastward 780 m later after Gandulan Junction, in where Jl. Perintis Kemerdekaan coming from Downtown Pemalang merges. Route 1 then goes twelve kilometers eastwards until a bend in Comal. It then curves northeastward for three kilometers, followed by another curving southeastward.
Route 1 enters Pekalongan Regency some 450 m later after crossing Sepait River. The route runs eastward, where it passes through the subdistricts of Siwalan, Wiradesa, and Tirto. It leaves Pekalongan Regency 5.5 km later when crossing Meduri River, and then enters Pekalongan City. In this segment, Route 1 is carried by Jl. Gajah Mada for two kilometers, when it is divided into two sections in front of Pekalongan Station. The eastbound sections follows Jl. Merdeka for 480 m. After crossing with Jl. Imam Bonjol and Jl. Patriot, it turns southward as Jl. Pemuda, while the westbound section still follows Jl. Gajah Mada. The two sections meet in front of Muhammadiyah College of Economics, where it continues southward as Jl. KH. Mas Mansyur, and has level crossing with Northern railway line. One kilometer later, it encounters Ponolawen Junction, where Route 1 turns eastward as Jl. Jend. Sudirman, Jl. Setiabudi, and then Jl. Sutomo. Ponolawen Junction also becomes an access to Kajen, the seat of Pekalongan Regency.
After entering Batang Regency 4.5 km later, it goes into the downtown. Continuing 3.3 km east, it makes a curving to the northeast. When passing Sambong Bridge 550 m later, it begins to enter a mountainous region that becomes a continuation of Dieng Plateau located in the south. Route 1 winds through the subdistricts of Kandeman, Tulis, Subah, Banyuputih, and Gringsing, in which there are many warungs and restaurants founded to cater all long-distance travellers. Continuing 32 km east, it encounters a three-way junction in Surodadi Village, where Route 1 goes eastward, while most traffic in North Coast of Java takes the newer road diverging from here. 470 m later, the old Great Post Road diverges from Route 1. All heavy vehicles aren't permitted to pass through Route 1 in this section considering its sharp climbs; instead they are obliged to take the curvaceous Great Post Road that passes through Alasroban Jungle. Route 1 and Great Post Road meets again 1.5 km northeastward. Route 1 then runs northeast for 360 m, and the mountainous segment before Semarang ends here. After encount
Indonesian National Route 1