Sălaj County is a county (județ) of Romania, located in the north-west of the country, in the historical regions of Crișana and Transylvania. It is bordered to the north by Satu Mare and Maramureș counties, to the west and south-west by Bihor County, and to the south-east by Cluj County. Zalău is the county seat, as well as its largest city.

Crișana is a geographical and historical region in north-western Romania, named after the Criș (Körös) River and its three tributaries: the Crișul Alb, Crișul Negru, and Crișul Repede. In Romania, the term is sometimes extended to include areas beyond the border, in Hungary; in this interpretation, the region is bounded to the east by the Apuseni Mountains, to the south by the Mureș River, to the north by the Someș River, and to the west by the Tisza River, the Romanian-Hungarian border cutting it in two. However, in Hungary, the area between the Tisza River and the Romanian border is usually known as Tiszántúl.