Meyers Orts- und Verkehrs-Lexikon des Deutschen Reichs (Meyers Gazetteer), online edition, with GOV (genealogy.net) for post-1945 Polish equivalents · meyersgaz.org / gov.genealogy.net
Mittenwalde 2) Mittenwalde, Templin, Potsdam, Brandenburg, Preussen
Meyers columns are place name, then Kreis, Regierungsbezirk, Province, State. Meyers lists six Mittenwalde in the empire; only entry 2) is in Kreis Templin, the Uckermark Kreis this row names. The geocoder had offered the Mittenwalde in Kreis Teltow, 100 km south. Coordinate from the modern gazetteer (Mittenwalde, Brandenburg, 53.1849/13.6636), which agrees with Meyers' 1912 point 53.1833/13.6667 to about 200 m.