Petershagen is a town in the Minden-Lübbecke district, in North Rhine-Westphalia, Germany. It lies on the Westphalian Mill Route. The core is formed by the districts of Petershagen and Lahde, located opposite each other on the Weser. Its typical dialect belongs, as with the Bremer Platt to the Southern Oldenburgish variety Northern Low Saxon, itself a dialect of the Low German language.