Corinth or Korinth (Greek: Κόρινθος, Kórinthos) is a modern town in the Peloponnese, a port and the capital of the prefecture of the same name. It was founded in 1858 after the modern village at Ancient Corinth was leveled by earthquake.
It is important to know that there is new Corinth and the Ancient one. If you go to "Corinth" that usually means you are going to the new one, i.e. all the archaelogical sites are not there, but a little outside the city (5 km).
Corinth has a population of 37,000.
The area is known to be inhabited at least since 6000BC. Nevertheless little in the town reminds its old glories, since it has been hit severely by earthquakes, destroying most of its old constructions.
It is very close and easily approachable from Athens through most transport means, buses, trains, cars.
If you want to go to the "old" Corinth ( with all the archaelogical sites and ruins, you can first go to the new Corinth and then take a bus from there to the old one. For that, you should go to the center of new Corinth and then ask people where the bus stop is. The bus stop should be located around a café and people there will tell you when the next bus goes (usually you will be waiting there a little). The bus has something something similar to "ARXAIA" written on it and takes you to the old part. You can buy a ticket in the bus (1,60 €). It is a good idea to stay in the bus a little while it is going through the old Corinth, because it gives you a nice, cheap tour. You could for example get out at the ancient theater (just ask the bus driver).
Upon entrance through Patras it is a convenient stop on the way to Athens or as a stop to explore the history rich area.
Most of the interesting and historical stuff is in old Corinth:
Some things to do in (new) Corinth! -Swim in "Kalamia" Beach in Corinth (also there is the statue of cynic philosopher "Diogenis" , that represents his encounter with the Alexander the Great in the past)
-Visit the Folklore Museum of Corinth (free entrance, open every day from 8am - 2pm, except from Tuesday)
-Taste Local Wines in the coffee-bars of the city (eg "Nostro Mondo" & "Dolce Amaro" cafe -bar in the port
-Taste Local Desserts (I propose: Honey & Milk -"Meli & Gala" in greek" or " Glykin Vraston"
-Visit the square in the port, where is a huge statue of the mythical horse "Pegasus"
To get to Athens, there is a bus stations near the sea. It is a little hidden and probably hard to find at first, but just keep asking people for the bus stop.
If you are in old Corinth, first take a bus from there to the new Corinth and ask the bus driver how to get to Athens. If you are lucky, he will take you along to a bus station (which comes after the city center and most people will have left the bus by that time). At that bus station, you will easily find a bus to Athens.