This dataset presents bulk organic geochemical measurements, including total carbon (TC), total nitrogen (TN), and stable carbon isotopes (δ13C), obtained by EA–IRMS analysis on peat samples collected from the Gushantun peat bog (42°18'22.1 N, 126°16' 57.7 E, 506m) in Northeast China. The samples were freeze dried and ground using an agate mortar and pestle. The homogenized material was packed into tin capsules for δ13C analysis and processed in the Stable Isotope Laboratory at the Swiss Federal Institute of Aquatic Science and Technology (Eawag), Kastanienbaum, Switzerland, using a Vario PYRO cube elemental analyzer (Elementar) coupled to an Isoprime visION isotope ratio mass spectrometer.