Messenia or Messinia (/məˈsiːniə/ mə-SEE-nee-ə; Greek: Μεσσηνία [mesiˈni.a]) is a regional unit (perifereiaki enotita) in the southwestern part of the Peloponnese region, in Greece. Until the implementation of the Kallikratis plan on 1 January 2011, Messenia was a prefecture (nomos) covering the same territory. The capital and largest city of Messenia is Kalamata.