Shakespeare's sources are a bit obscure for this somewhat mysterious play. A dialogue by Lucian called Timon the Misanthrope and the life of Timon of Phlius, a real philosopher, have been suggested, not very convincingly. It could be a story that Shakespeare made up.
Unsurprisingly, it's set in and around Athens. The earlier part of the play takes place in Athens, both at Timon's house and that of other Athenians. The latter part of the play takes place in the countryside around Athens.
Timon of Athens
Pericles, Timon of Athens and Cymbeline.
Timon of Athens
Timon of Athens.
The first scene of Timon of Athens establishes very clearly Timon's recklessly generous behaviour by showing his generosity to a poet, painter, and jeweller, as well as Ventidius, Lucilius, Apemantus and Alcibiades, who will become important later in the play.
Speculation shows it was never finished.
Toshinori Fushimi has written: 'A note on 'Timon of Athens''
pale fire
King John. Timon of Athens. Cymbeline. The Two Gentlemen of Verona.
The Comedy of Errors, Pericles, A Midsummer Night's Dream, Timon of Athens.
Pericles, Troilus and Cressida, Henry VIII, King John, Timon of Athens