Croatia is well represented in the Geography & Map Reading Room, which has hundreds of single and set maps, as well as atlases, showing Croatia, Dalmatia or former Yugoslavia. Many maps of Croatia are cataloged individually and can be identified using the Library of Congress online catalog. In addition, a significant number of maps of Croatia from 1745 through 1970 are discoverable with collection level records. Croatia is also represented in single maps showing the Balkan Peninsula, of which there are over four hundred in the Geography & Map collection, half of which are cataloged individually and the other half cataloged at the collection level. Maps from or about Austro-Hungary may also be relevant to the study of Croatia. All of the maps are available in the Geography and Map Reading Room and you will need to ask for assistance to view them.
Interesting examples include city maps, tourist maps, road maps, an atlas of Slovak culture in Croatia, a once secret map from 1972 of the city of Rijeka composed by the Soviet army identifying government, military, transportation, and industrial facilities, and maps produced by the Central Intelligence Agency related to the Yugoslav War, 1991-1995.
Possibly the oldest relevant item is Martin Waldseemüller's 1516 Carta marina. Plate Two of this map shows the Balkans and identifies two cities located in Croatia - Sagabria (Zagreb) and Gernouo (Zrnovo). Dalmatia and Solavonia (Sclavonia) are identified on a Ptolemaic map of the Balkan Peninsula, from the 1541 Vienna edition of Tabula noua Graeciae, Sclauoniae, et Bulgariae. Geographia [New Map of the Greeks, Slavs, and Bulgarians. Geography]. Several other rare maps in the collection depict Croatia such as the beautiful, hand-colored Viennese map of 1809, Karte vom Koenigreiche Ungarn, mit Einschluss der Königreiche Kroazien und Slavonien, by Joseph M. Liechtenstern (1765-1828). From the Hungarian perspective is Repertorium locorum objectorumque in XII. tabulis Mappae regnorum Hungariae, Slavoniae, Croatiae, et Confiniorum Militarium from 1808 by János Lipszky, (1766-1826). This map, the first complete map of the Hungarian Empire, is still valued by researchers today, for its accuracy and gazetteer.
For Croatia as part of the Austro-Hungarian Empire, the Library has digitized Spezialkarte der Österreichisch-Ungarischen Monarchie, a series of maps prepared by the Austro-Hungarian monarchy's Militärgeographisches Institut beginning around 1875, and issued in later editions up through the 1940s. In total the set contains over 1,000 maps in multiple editions. Use the graphic index following the detailed example in the Austro Hungarian section of Cartographic Resources for Genealogical Research: Eastern Europe and Russia to identify the geographic location of interest. The digitized maps are available in the manifest. Let this map of Vukovar serve as an example of Croatian content from this series (n.b. the link will download the map). The set is complicated, so feel free to ask questions of the specialists in the Geography and Map Reading Room.
The Geography and Map Division (G&M) has custody of the largest and most comprehensive cartographic collection in the world with collections numbering over 5.5 million maps, 100,000 atlases, 8,000 reference works, over 5000 globes and globe gores, 3,000 raised relief models, over 130,000 microfiche/film, and a large number of cartographic materials in other formats.