The Ukrainian region of Donetsk is a seven-letter word, and the region of Ruthenia is an eight-letter word. Donetsk is an industrial and coal mining center in eastern Ukraine, located on the Kalmius River. It is the administrative center of the Donetsk Oblast, and is one of the largest cities in Ukraine. Ruthenia is a historical region in Eastern Europe, located in present-day Ukraine and parts of Romania, Hungary, Slovakia, and Poland. It was part of the Kingdom of Hungary from the 10th century until 1918, when it became part of Czechoslovakia.