  We present results of a wideband high-resolution polarization study of Hydra
A, one of the most luminous FR I radio galaxies known and amongst the most
well-studied. The radio emission from this source displays extremely large
Faraday rotation measures (RM), ranging from -12300 rad m$^{-2}$ to 5000 rad
m$^{-2}$, the majority of which are believed to originate from magnetized
thermal gas external to the radio tails. The radio emission from both tails
strongly depolarizes with decreasing frequency. The depolarization, as a
function of wavelength, is commonly non-monotonic, often showing oscillatory
behavior, with strongly non-linear rotation of the polarization position angle
with $\lambda^2$. A simple model, based on the RM screen derived from the high
frequency, high resolution data, predicts the lower frequency depolarization
remarkably well. The success of this model indicates the majority of the
depolarization can be attributed to fluctuations in the magnetic field on
scales $< 1500$ pc, suggesting the presence of turbulent magnetic
field/electron density structures on sub-kpc scales within a Faraday rotating
(FR) medium.
