ADELNAU, a circle in the province of Posen, in Prussia. It extends over 357 square miles, or 228,480 acres, and contains, in four cities and 107 villages, 52,530 inhabitants. The river Prosna waters the east side, and the Ollabok the centre of the circle. There are several smaller rivers, and some lakes, the most considerable of which bears the name of the chief place near to which it is found. It is a poor district, abounding with woods and game, and yielding fresh-water fish in plenty. It is very deficient in corn and cattle. The capital, of the same name, contains two Catholic and one Lutheran church, and a synagogue, with 200 houses, and 1930 inhabitants.