Aiud is a city located in Alba County, Transylvania, Romania. The city's population is 21,307. It has the status of municipiu. The city derives it…Aiud is a city located in Alba County, Transylvania, Romania. The city's population is 21,307. It has the status of municipiu. The city derives its name ultimately from Saint Giles, to whom the first church in the settlement was dedicated when built.