Long-term deployment of dryland cropping systems can alter soil chemical properties in ways that lead to lower soil fertility. Few long-term experiments have investigated cropping intensity, tillage, and nitrogen fertilization effects on soil chemical properties in the northern Great Plains. Near-surface (0-7.6 cm) soil chemistry data were evaluated from two cropping systems (continuous cropping and crop-fallow), each split by tillage (no-, minimum, and conventional) and nitrogen rate (no/low, medium, high) treatments for 16 years. The experiment was established in 1984 on the Area IV Soil Conservation Districts Cooperative Research Farm near Mandan, North Dakota USA. Soil cores were collected in 1983 (prior to establishment of treatments) and again in 1999 from the surface 7.6-cm depth near the middle of each experimental plot using a hydraulic probe. Samples were dried, mechanically ground, and analyzed within 6 wk of collection. Soil pH was measured in a 1:1 soil/water mixture (by mass) with an ion-selective glass electrode. Exchangeable cations (Ca, Mg, K, and Na) were estimated by atomic absorption spectrometry. Data may be used to better understand cropping, tillage, and nitrogen fertilization effects on soil pH and exchangeable cations under dryland conditions in a semiarid continental climate. Applicable USDA soil types include Temvik, Wilton, Grassna, Linton, Mandan, and Williams.Updated versions of two Excel files were uploaded on 5 February 2025 to remove extraneous information in the metadata tab. We apologize for the oversight.