The area of northern Bulgaria is 24,535 sq. m.; of Eastern Rumelia 12,705 sq. m.; of united Bulgaria, 37,240 sq. m. According to the census of the 12th of January 1906, the population of northern Bulgaria was 2,853,704; of Eastern Rumelia, 1,174,535; of united Bulgaria, 4,028,239 or 88 per sq. m. Bulgaria thus ranks between Rumania and Portugal in regard to area; between the Netherlands and Switzerland in regard to population: in density of population it may be compared with Spain and Greece.
The first census of united Bulgaria was taken in 1888: it gave the total population as 3,154,375. In January 1893 the population was 3,310,713; in January 1901, 3,744,283.
The movement of the population at intervals of five years has been as follows: -
 Excess of births over deaths.
The death-rate shows a tendency to rise. In the five years 1882-1886 the mean death-rate was 18.0 per 1000; in 1887-1891, 20.4; in 1892-1896, 27.0; in 1897-1902, 23.92. Infant mortality is high, especially among the peasants. As the less healthy infants rarely survive, the adult population is in general robust, hardy and long-lived. The census of January 1901 gives 2719 persons of 100 years and upwards. Young men, as a rule, marry betore the age of twenty-five, girls before eighteen. The number of illegitimate births is inconsiderable, averaging only 0.12 of the total. The population according to sex in 1901 is given as 1,909,567 males and 1,834,716 females, or 51 males to 49 females. A somewhat similar disparity may be observed in the other countries of the Peninsula. Classified according to occupation, 2,802,603 persons, or 74.85% of the population, are engaged in agriculture; 360,834 in various productive industries; 118,824 in the service of the government or the exercise of liberal professions, and 148,899 in commerce.
The population according to race cannot be stated with absolute accuracy, but it is approximately shown by the census of 1901, which gives the various nationalities according to language as follows: - Bulgars, 2,888,219; Turks, 531,240; Rumans, 71,063; Greeks, 66,635; Gipsies (Tziganes), 89,549; Jews (Spanish speaking), 33,661; Tatars, 18,884; Armenians, 14,581; other nationalities, 30,451. The Bulgarian inhabitants of the Peninsula beyond the limits of the principality may, perhaps, be estimated at 1,500,000 or 1,600,000, and the grand total of the race possibly reaches 5,500,000.