Estonia is 3.3 times larger than Montenegro.
Area: 45,228 km2 World Factbook
Population: 1,257,921 (July 2014) World Factbook
Estonia, officially the Republic of Estonia, is a country in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia, and to the east by Lake Peipus and Russia. Wikipedia
Area: 13,812 km2 World Factbook
Population: 650,036 (July 2014) World Factbook
Montenegro is a country in Southeastern Europe. It has a coast on the Adriatic Sea to the south-west and is bordered by Croatia to the west, Bosnia and Herzegovina to the northwest, Serbia to the northeast, Kosovo to the east and Albania to the south-east. Wikipedia