Antigone, like Oedipus the King, is set in that disaster-prone city-state known as Thebes. Though most Greek playwrights were from Athens, their plays are hardly ever set there. This is not because they had no hometown pride. In fact, they weren't allowed to set their plays in Athens. It seems Athenians preferred a little objective distance when examining tragedy. Though the plays were set in other places than Athens, they did take on hot-button Athenian issues. For example in Antigone the clash between Creon and Antigone can be seen as symbolic of the many cultural clashes going on in Athens at the time.
Probably the most prominent Athenian culture clash we see in Antigone is the laws of the state vs. religious fundamentalism. Sophocles was a religious conservative and was a member of several cults. However, in his time, a group called the Sophists was on the rise. These men valued rationality over what they thought of as superstition. Any Athenian even moderately aware of current events wouldn't have missed the warning encoded in Sophocles' play. When Creon, the hyper-rational representative of law and order falls to the will of the gods, it's pretty clear where Sophocles stood on this hot-button issue.
Athenians also liked objective distance in terms of time. Tragedies were almost always set in Greece's distant past. Sophocles and his buddies adapted their stories from the Greeks' rich oral tradition. These tales of gods and heroes had been handed down for generations. Antigone was an ancient figure even to the ancient Greeks.
Most specifically the play is set in front of the palace of Thebes. This place has been the sight of much tragedy for Antigone's family. It's where her mother/grandmother, Jocasta, committed suicide, and where her brother/father Oedipus discovered his shame and gouged out his own eyes. Not to mention the fact that the palace represents the throne that her brothers have just killed each other over. There's really no more fitting place for Antigone to receive her own tragic fate.