This dataset contains manually developed 5-, 10-, and 500-ft contours for the Harney Basin, Oregon aquifer system shallow and deep potentiometric-surface maps. The potentiometric-surfaces show altitude at the water-table surface (shallow) and at which the water level would have risen in tightly-cased wells deeper than 100 ft (deep) and generally represents synoptic conditions during February–March of 2018. The water-table map was developed using groundwater-level measurements from shallow wells (generally less than 100 ft deep in the lowlands) and the altitudes of springs and gaining stream reaches and constrained by the altitude of the land surface. The deeper potentiometric-surface map was developed using measurements from wells generally more than 100 ft deep in the lowlands. The hydraulic-head distributions depicted are generalizations. The large study area, availability of water-level measurements, the distribution of wells across Harney Basin, and resource limitations precluded mapping all the complexities of the head distribution. Contours are most detailed and have 10-ft intervals (with the exception of the 4,095-ft contour) in the Harney Basin lowlands where data are more abundant, and the land surface is relatively flat. Groundwater heads of 4,200 ft or more were mapped using 500-ft contour intervals and generally coincide with upland areas where wells are sparse and groundwater head is strongly controlled by topography.