Hadiach is a city in Myrhorod Raion, Poltava Oblast in the central-east part of Ukraine. It hosts the administration of Hadiach urban hromada. Ha…Hadiach is a city in Myrhorod Raion, Poltava Oblast in the central-east part of Ukraine. It hosts the administration of Hadiach urban hromada. Hadiach is located on the Psel River. Population: 22,851.