Equipment is described for electrical measurements under hydrostatic pressures to 30 kilobar over the low to room temperature range. The piston and cylinder type pressure vessel of the high‐pressure cryostat is actuated directly by a hydraulic ram at room temperature. Thermal isolation is achieved through use of long tension and compression members. Details about the self‐stressing, double‐walled cylinder are provided. Both the Bi I–II transition and an n–InSb manometer have been used for pressure calibration.