Purgatory - is it a place or state? According to Catholicism, does purgatory refer to a place or state? Has it ever been described as a place and then later a state, or vice-versa?
To the best of my knowledge, the details of purgatory have never been set out in an official Vatican document (like a papal bull, council decree, etc.). The magisterium of the church is somewhat vague on this point. (For some well-cited reading on various aspects of purgatory, see New Advent's Catholic Encyclopedia.)

Somewhat recently, however, Pope Benedict tried to shine some light on the matter. In a January 2011 talk about St. Catherine of Genoa, author of a treatise on purgatory, the pope agreed with the saint's conviction that "purgatory was not a place, but a process." 


  "'The soul that is aware of the immense love and perfect justice of God consequently suffers for not having responded correctly and perfectly to that love,' the pope said, adding that the suffering is purgatory."