Ethnographic cartography of the Balkans in the late 19th and early 20th century

The decline of the Ottoman Empire in the late 19th century led to fierce territorial competition between the Greeks, Serbs, Bulgarians and Turks, in particular over the contested region of Macedonia. As a result, a large number of maps attempting to depict the ethnic demographics of the Balkans were published at this time, particularly from 1876 onwards, following a Serb and Montenegrin uprising and the Russo-Turkish War of 1877-1878. Maps were produced and used by the various sides to justify their claims. The phenomenon has been labelled as a "map mania".

Greeks, Serbs, and Bulgarians tended to manipulate and distort the maps, also relying on fake sources and modifying old data. The maps depicted ethnic groups as blocks of solid colors, obscured ethnic diversity, merged sub-groups into dominant ethnicities, and ignored population density. In order to provide an impression of uniformity and stability, substantial minorities (even up to 49 percent in some cases) and scattered communities were omitted; map scale was adjusted according to the map's aim whether to include or exclude specific minorities.

The maps by Ami Boué and Guillaume Lejean were influential in the early period, and were generally favorable to the Bulgarians, but they greatly exaggerated Albanian presence towards the south, and their reputation suffered as a result. The 1876 map by Heinrich Kiepert was particularly influential and used at the Congress of Berlin. In response, three pro-Greek maps were generated due to Greek efforts (Stanford, Bianconi, Synvet), but these had little impact, and no one outside Greece took them seriously. The standard Greek practice in all the maps it produced was to consider as Greeks not only the Greek-speakers, but also all the Christian Vlachs (Aromanians and Megleno-Romanians), the Christian Albanians, and the Exarchist Slavs, an approach rejected by international figures.