Greece Interstate 8 is an old highway linking the cities of Patras, Corinth and Athens. Until the 1960s when the toll superhighway named GR-8A opened, it was the major and the only route for Athens and the Peloponnese as well as Corinth and Patras. The highway passes on the northern part of the Saronic Gulf and for 5 km in the Isthmus of Corinth and after, in the southern part of the Gulf of Corinth and ends in downtown Patras. It runs into three prefectures of Achaea, Corinth and Attica.
The highway passes through the north suburban Patras places and the northern part of the Panachaicus. After that, it passes into the plains south to the hills wherre for about 5 km, the superhighway passes south, the rest up to Derveni passes near the hills and the mountains. It runs through the rest of the route within the Gulf of Corinth with a plain up to Corinth. It passes through downtown Corinth and goes uphill and the old branch passes through Isthmia and into the southern part of the canal as a drawbridge, the newer branch of what it used to be a toll highway ran in the middle of the canal and is still Corinth's touristic attraction today as the view of 4 km of the canal can be seen.
The highway runs north of the Saronic Gulf and into the mounain ranges but from the refinery to Kineta and after runs through the southern part of the rocky Kakia Skala where it ends west of Megara where the old branch runs through Megara, the former superhighway branch runs south of GR-8A and the middle branch runs north of GR-8 and bypassing Megara. Another mountain is in the south and is followed by Eleusis Refinery and Eleusis. It finally ends near the Eleusis interchnage in the eastern part.
Several movies, one in Kakia Skala and one treacherous curve west of Derveni near the railway crossing? were filmed in the 1950s.
In 1991 and 1993, the freeway was closed and was detoured to this highway for detour and was used again several times during construction over the superhighway.
In 1997, the old road included the old superhighway that ran from what is now the junction with GR-7 up to where the old Isthmia tolls used to be now lies 3 km E near the Loutraki Interchange.
The future high-speed railway from Corinth to Megara will run within the highway.
Here are places where the highway runs through and bypasses:
I - Old Athens-Corinth Highway:
- Sacred Way or Iera Odos
- junction with GR-3
- Eleusis Refinery
- Neos Peramos
- Megara, bypasses next to the superhighway in the south and the branch of a old superhighway
- Agioi Theodoroi
- Corinth Refinery along with the branch of what it used to be a toll highway
- Isthmia, bypasses
- Corinth Canal (two branches)
- junction of GR-7, old highway
II - Old Athens-Patras Highway
- junction of GR-7 (western branch)
- north of Velo
- Kato Domini
- Kato Loutro
- Aigio, junction with GR-31
- south of Psathopyrgos
- Agios Vasileios
- junction with GR-5 and GR-8A (eastbound lanes)
- Agios Georgios
- south of the University of Patras
- Junction with the Patras By-pass
- Panepistemiou Avenue
- downtown Patras (western terminus)