From Act I of the original Moscow Art Theatre production of UNCLE VANYA

From Act III of the original Moscow Art Theatre production of UNCLE VANYA

From Act IV ​of the original Moscow Art Theatre production of UNCLE VANYA

The original Astrov and Yelena -- played by Konstantin Stanislavski and his wife Maria Lilina 

Uncle Vanya is a reworking of Chekhov’s 1889 play, The Wood Demon (Леший). The title of that play refers to the character of Doctor Krushchov, the original of Astrov in this play.
The subtitle of Uncle Vanya, “Scenes from Country Life” is also the subtitle of Ivan Turgenev’s 1855 play (not staged until 1872), A Month in the Country. 

SETTING
​According to Michael Frayn, Donald Rayfield states that the setting of Uncle Vanya is “a tired and over-populated central Russian landscape somewhere on the railway line between Serpukhov and Kharkov.”
In other words, south of Moscow, somewhere in the present day oblasts of Tula, Oryol, Kursk, or Belgorod. The fact that Serebryakov and Yelena are headed to Kharkov (in present-day Ukraine) at the end of the play implies to me that they are towards the southern end of this geographic area. 

A side note: Chekhov’s country estate at Melikhovo, where he wrote Uncle Vanya, is roughly halfway between Moscow and Serpukhov.