  We investigate the X-ray properties of the powerful radio galaxy Hercules A
(3C 348) using ROSAT HRI, PSPC and ASCA observations. The ASCA data are well
fit by a thermal plasma model with a temperature of about 4.3 keV and
abundances 0.4 solar. The HRI observation clearly reveals extended and
elongated X-ray emission. For radii greater than 10 arcsec, the surface
brightness profile perpendicular to the elongation is well fit by an isothermal
beta--model with beta = 0.63 and a core radius of about 120 kpc. We derive a
total mass of the putative cluster of 8.4e+13 M_sun and a gas mass fraction of
about 18 per cent. The inner part of the surface brightness profile clealry
reveals the presence of a point source, which contributes about 8 per cent to
the total flux. The 0.1-2.4 keV luminosity of the point-like and the extended
emission is 3.4e+43 and 4.3e+44 erg/s, respectively. After subtracting the
cluster X-ray emission from the HRI image, residual structures are visible,
which partly coincide with the radio jet and lobes. This indicates an
interaction of the radio jet with the intracluster medium.
