Istiaia (, before 1913: Ξηροχώρι - Xirochori) is a town and a former municipality in Euboea, Greece. It was named after the ancient town Histiaea, which was mentioned by the ancient Greek poet Homer. Since the 2011 local government reform it is part of the municipality Istiaia-Aidipsos, of which it is the seat and a municipal unit. At the 2011 census the population was 7,091 for the municipal unit and 5,522 for the community.

Istiaia (, before 1913: Ξηροχώρι - Xirochori) is a town and a former municipality in Euboea, Greece. It was named after the ancient town Histiaea, which was mentioned by the ancient Greek poet Homer. Since the 2011 local government reform it is part of the municipality Istiaia-Aidipsos, of which it is the seat and a municipal unit. At the 2011 census the population was 7,091 for the municipal unit and 5,522 for the community.