The city derives its name ultimately from Saint Giles (Aegidius), to whom the first church in the settlement was dedicated when built.

[3] Aiud comprises the city proper and the ten villages it administers, in order of population: At the 2011 census, the ethnic composition of the city was:[4][dead link‍] Aiud has a humid continental climate (Cfb in the Köppen climate classification).

The citadel is fairly small, with a perimeter of 350 metres (1,150 feet), and it is in the form of an irregular pentagon.

The earliest documented evidence of the citadel extant today dates from 7 November 1293, a privilege issued by King Ladislaus IV of Hungary (1272–1290), but local tradition holds that the first stone watch tower was finished during the Mongol invasion of Europe in 1241.

It is located in the beautiful City Park, and was erected in memory of the students who fought against the Habsburg invasion in 1704.

Most of Aiud's population are Christian, but they also come from a variety of denominations, including Catholicism and Eastern Orthodoxy and well as Reformed, Unitarian, Baptist, and Evangelical faiths.

The Orthodox cathedral is located in the southeast of the city, and is an impressive building with high ceilings and wonderful domes.

The Roman Catholic church, albeit being smaller and less imposing than the Orthodox Cathedral, is built in the Baroque style.

The Reformed church mainly serves the Hungarian minority of Aiud, which played a big role in the identity of the city in terms of education, art, architecture and more.

The college, named after Gabriel Bethlen, Prince of Transylvania (1613–1629), was founded in 1622 in Alba-Iulia, the capital city of Alba County, and it was then moved to Aiud.

As well as rich culture, Aiud is also littered with wonderful scenic tourist attractions in terms of the environment.

This provides a strong base for ecotourism in the area, as there are beautiful forests, hills and mountains and fresh air.

Aiud is easily accessible from all parts of Romania due to its position in the centre of the country and its road network.

The city is located on the national road running from Bucharest to Oradea and then crossing the Hungarian border to Budapest.

Aiud is an important railway hub and is served frequently by CFR national trains.