  The de Haas - van Alphen effect and energy band calculations are used to
study angular dependent extremal areas and effective masses of the Fermi
surface of the highly correlated antiferromagnetic material CeRhIn$_5$. The
agreement between experiment and theory is reasonable for the areas measured
with the field applied along the (100) axis of the tetragonal structure, but
disagree in size for the areas observed for the field applied along the (001)
axis where the antiferromagnetic spin alignment is occurring. Detailed
comparisons between experiment and theory are given.
