Gilan Province is one of the 31 provinces of Iran, in the northwest of the country. It lies along the Caspian Sea, in Iran's Region 3, west of the province of Mazandaran, east of the province of Ardabil, and north of the provinces of Zanjan and Qazvin. It borders Azerbaijan in the north.

Mazandaran province is one of the 31 provinces of Iran, located along the southern coast of the Caspian Sea and in the adjacent Central Alborz mountain range, in central-northern part of the country. The province, founded in 1937, covers an area of 23,842 km2.