Reghin is a city in Mureș County, Transylvania, central Romania, on the Mureș River. As of 2021, it had a population of 29,742, making it the …Reghin is a city in Mureș County, Transylvania, central Romania, on the Mureș River. As of 2021, it had a population of 29,742, making it the second biggest city of the Mureș county, just behind the capital Târgu Mureș and ahead of Sighișoara.