Sillamäe is a town in Ida-Viru County in the northereastern part of Estonia, on the southern coast of the Gulf of Finland. It has a population of 12,…Sillamäe is a town in Ida-Viru County in the northereastern part of Estonia, on the southern coast of the Gulf of Finland. It has a population of 12,439 and covers an area of 10.54 km². Sillamäe is located at the mouth of Sõtke River. Its population is predominantly Russian-speaking.