The Bulgarians, who constitute 77.14% of the inhabitants of the kingdom, are found in their purest type in the mountain districts, the Ottoman conquest and subsequent colonization having introduced a mixed population into the plains.

The devastation of the country which followed the Turkish invasion resulted in the extirpation or flight of a large proportion of the Bulgarian inhabitants of the lowlands, who were replaced by Turkish colonists. The mountainous districts, however, retained their original population and sheltered large numbers of the fugitives. The passage of the Turkish armies during the wars with Austria, Poland and Russia led to further Bulgarian emigrations. The flight to the Banat, where 22,000 Bulgarians still remain, took place in 1730. At the beginning of the 19th century the majority of the population of the Eastern Rumelian plain was Turkish. The Turkish colony, however, declined, partly in consequence of the drain caused by military service, while the Bulgarian remnant increased, notwithstanding a considerable emigration to Bessarabia before and after the Russo-Turkish campaign of 1828. Efforts were made by the Porte to strengthen the Moslem element by planting colonies of Tatars in 1861 and Circassians in 1864. The advance of the Russian army in 1877-1878 caused an enormous exodus of the Turkish population, of which only a small proportion returned to settle permanently.

The emigration continued after the conclusion of peace, and is still in progress, notwithstanding the efforts of the Bulgarian government to arrest it. In twenty years (1879-1899), at least 150,000 Turkish peasants left Bulgaria. Much of the land thus abandoned still remains unoccupied. On the other hand, a considerable influx of Bulgarians from Macedonia, the vilayet of Adrianople, Bessarabia, and the Dobrudja took place within the same period, and the inhabitants of the mountain villages show a tendency to migrate into the richer districts of the plains.

The northern slopes of the Balkans from Belogradchik to Elena are inhabited almost exclusively by Bulgarians; in Eastern Rumelia the national element is strongest in the Sredna Gora and Rhodope. Possibly the most genuine representatives of the race are the Pomaks or Mahommedan Bulgarians, whose conversion to Islam preserved their women from the licence of the Turkish conqueror; they inhabit the highlands of Rhodope and certain districts in the neighbourhood of Lovtcha (Lovetch) and Plevna. Retaining their Bulgarian speech and many ancient national usages, they may be compared with the indigenous Cretan, Bosnian and Albanian Moslems. The Pomaks in the principality are estimated at 26,000, but their numbers are declining. In the north-eastern district between the Yantra and the Black Sea the Bulgarian race is as yet thinly represented; most of the inhabitants are Turks, a quiet, submissive, agricultural population, which unfortunately shows a tendency to emigrate. The Black Sea coast is inhabited by a variety of races. The Greek element is strong in the maritime towns, and displays its natural aptitude for navigation and commerce.

The Gagäuzi, a peculiar race of Turkish-speaking Christians, inhabit the littoral from Cape Eminé to Cape Kaliakra: they are of Turanian origin and descend from the ancient Kumani. The valleys of the Maritza and Arda are occupied by a mixed population consisting of Bulgarians, Greeks and Turks; the principal Greek colonies are in Stanimaka, Kavakly and Philippopolis. The origin of the peculiar Shôp tribe which inhabits the mountain tracts of Sofia, Breznik and Radomir is a mystery. The Shôps are conceivably a remnant of the aboriginal race which remained undisturbed in its mountain home during the Slavonic and Bulgarian incursions: they cling with much tenacity to their distinctive customs, apparel and dialect. The considerable Vlach or Ruman colony in the Danubian districts dates from the 18th century, when large numbers of Walachian peasants sought a refuge on Turkish soil from the tyranny of the boyars or nobles: the department of Vidin alone contains 36 Ruman villages with a population of 30,550. Especially interesting is the race of nomad shepherds from the Macedonian and the Aegean coast who come in thousands every summer to pasture their flocks on the Bulgarian mountains; they are divided into two tribes - the Kutzovlachs, or "lame Vlachs," who speak Rumanian, and the Hellenized Karakatchans or "black shepherds" (compare the Morlachs, or Mavro-vlachs, μαῦροι βλάχες, of Dalmatia), who speak Greek. The Tatars, a peaceable, industrious race, are chiefly found in the neighbourhood of Varna and Silistria; they were introduced as colonists by the Turkish government in 1861. They may be reckoned at 12,000. The gipsies, who are scattered in considerable numbers throughout the country, came into Bulgaria in the 14th century.

They are for the most part Moslems, and retain their ancient Indian speech. They live in the utmost poverty, occupy separate cantonments in the villages, and are treated as outcasts by the rest of the population. The Bulgarians, being of mixed origin, possess few salient physical characteristics. The Slavonic type is far less pronounced than among the kindred races; the Ugrian or Finnish cast of features occasionally asserts itself in the central Balkans. The face is generally oval, the nose straight, the jaw somewhat heavy. The men, as a rule, are rather below middle height, compactly built, and, among the peasantry, very muscular; the women are generally deficient in beauty and rapidly grow old. The upper class, the so-called intelligenzia, is physically very inferior to the rural population.