Kuusalu is a small borough in Harju County, northern Estonia. It is the administrative centre of Kuusalu Parish. Kuusalu has a population of 1,220 (as of 1 January 2010).

The territory of modern Harju County consists mostly of two ancient Estonian counties: Revala, around what is now Tallinn, and Harjumaa, which was situated south of Revala and presently rests mostly in Rapla County. Lindanise, then a small trading post at the Gulf of Finland, served as the capital of Revala. It eventually grew into the mostly German-populated Hanseatic town of Reval and later into the Estonian capital, Tallinn.