After the conquest of Dacia by Trajan (106), the Roman Empire border stood atop the Meseș Mountains, just 5 km (3.1 mi) away from the city[citation needed].

The first written mention about Zalău, was in the "Gesta Hungarorum", also called the "Chronicle of Anonymous" (probably notary of the King Béla III of Hungary), published around year 1200.

At the end of the 16th century, the city had an independent administrative leadership, composed of 33 elected senators (one of whom was the mayor), a notary, a registrar and a treasurer.

After Transylvania had been annexed to the Habsburg Empire, the city experienced an economic decline due to the infusion of products from Western Europe.

After Michael the Brave's victory in the Battle of Guruslău on 3 August 1601, Zalău received administrative, legislative, fiscal and military own rules, which provided real autonomy freedoms to citizens.

A chronicle from the 17th century, first mentioned the main crafts of city residents: belt-makers, potters, wheelwrights, shoemakers, butchers, tailors, blacksmiths, carpenters, hat makers and armorers.

On 9 November 1714, Charles XII of Sweden rested for a night in a building on Király street (now named after Corneliu Coposu) with an acquaintance György Zoványi as is indicated by a notice still on the house.

On 8 September 1940, upon arrival in Zalău, the Hungarian Army killed 10 people just outside the city; in the following days, the Nușfalău, Treznea, and Ip massacres were perpetrated in nearby villages.

In the 1970s with the working-class population expanding, housing estates of high-rise blocks of flats were built in both the centre and the outskirts of the town.

The town has two nationally accredited University colleges, a public library, one museum, an art gallery, more than four hotels, a motel, and two student halls of residence.

It is located in the central part of Sălaj County, in the Zalău River watershed, between three narrow valleys in the Meseș Mountains.

It neighbours Țara Maramureșului and Satu Mare County, in the northwestern part of the historical region of Transylvania, which in the past was a mainly independent small state but since 1918 has belonged to Romania (except between September 1940 and October 1944, when it was under the administration of Hungary following the Second Vienna Award).

[citation needed] The most important of the 24 monuments and buildings in the county capital of Zalău are: "Transilvania" (theatre in 1895), the city hall (court and seat of the prefects office in 1889), the Roman Catholic Church (1878), the reformed church (1904–1907), the Greek Catholic "Dormition of the Theotokos Church" (1930–1934), the Orthodox deanery (built in the late 19th century), the Historical Museum (built about 1900 – casino of the artisans fellowship), the primary school "Simion Bărnuțiu" (girls' school in 1895) and the National College Silvania (Reformed College in 1860), all these being valuable urbanistic elements for the historical and cultural patrimony of the land.

The famous statuary group Wesselényi Monument of the heroic Hungarian nobleman with the same name (1902) by János Fadrusz, and the bust made in the honour of Simion Bărnuțiu by Romul Ladea are worth visiting as well.

There is a statue of Baron Wesselényi in Iuliu Maniu Square of the town center; the Tuhutum Memorial (both made by János Fadrusz in 1902); the Zalău County Museum of History and Art displays artifacts ranging from neolithic times to modern times, with a focus on the Roman period and hosts works of modern art.

The location had various names: "Ziloc" in 1220, "Oppidum Zilah" in 1473, "Zila" in 1601, and "Zilahu" and "Zalahu" in the 19th century, or forms of German toponymy "Waltenberg" and "Zillenmarkt".