ORTWIN is a program for the state-wide inquiry of the localities, postal codes and telephone selections in Germany. It finds postal zip codes, telephone pre selections, coordinates and ground level elevations. The program determines municipal codes, local center points, car license codes, topographic maps, Unlocodes and much more. It arranges localities hierarchically into the structures federal state, administrative district, rural district, town, municipality, local quarter and domicile. The program performs perimeter searches and distance calculations. It finds landscapes on different levels, natural units and snow- and wind load zones of all localities. In a radius around a place or around a postal code area covered localities and postal areas can be clearly represented by a comfortable perimeter search. They can also be arranged in a list, stored as a file and printed. For the local inquiries and perimeter searches a data base with more than 105.000 geo coded localities is available. The program represents local data, determined by local inquiries and perimeter searches, in graphic overviews and data lists. The program supports conversions between different coordinate systems and the distance calculation between the places. It calculates with Gauss Krueger coordinates referring to the Potsdam Datum (Bessel ellipsoid, Rauenberg) and with Geographic Coordinates on the geodetic datum WGS84. It also works with UTM coordinates, which refer to the datum ETRS89 (GRS80, geocentric). The functionality of the program is described in a detailed electronic manual. The program can be run on most common networks and it is possible to use Terminal Services on WINDOWS Servers. The client installations are done automatically.