Daylam, also known in the plural form Daylaman (and variants such as Dailam, Deylam, and Deilam) was the name of a mountainous region lying between Gilan, Qazvin and Zanjan.

Daylam, also known in the plural form Daylaman (and variants such as Dailam, Deylam, and Deilam) was the name of a mountainous region lying between Gilan, Qazvin and Zanjan.