Tallinn is the largest city and capital with almost 395,000 people. The next largest city is Tartu with 97,000 people.
Estonians are Finnic people who speak Estonian, which is closely related to Finnish. The ethnic breakdown is currently 69% Estonian, 25% Russian, 2% Ukranian, 1% Belarusians, 0.8% Finns and 1.6% other. Before WW2, ethnic Estonians made up 88% of the total population, at which time the largest minority groups were Germans, Russians, Swedes, Jews, Latvians, Poles, Finns and Ingrians. This has changed quite a bit.
Between 1945 and 1989, the percentage of ethnic Estonians in the country dropped to only 61% due to a Soviet program promoting the mass immigration of workers from Russia, Ukraine and Belarus and Stalin's deportations and executions. By the 1980's, this was seen as a national catastrophe. After the reconstitution of independence, large-scale emigration of ethnic Russians occurred and ethnic Estonians in the country rose to 69%.
Today, Estonia is an ethnically heterogeneous country, with one county having 99% Estonians. 13 out of the country's 15 counties are more than 80% ethnic Estonian.