  Constraining the behavior of cosmic ray data observed at Earth requires a
precise understanding of how the cosmic rays propagate in the interstellar
medium. The interstellar medium is not homogeneous; although turbulent magnetic
fields dominate over large scales, small coherent regions of magnetic field
exist on scales relevant to particle propagation in the nearby Galaxy. Guided
propagation through a coherent field is significantly different from random
particle diffusion and could be the explanation of spatial anisotropies in the
observed cosmic rays. We present a Monte Carlo code to propagate cosmic
particle through realistic magnetic field structures. We discuss the details of
the model as well as some preliminary studies which indicate that coherent
magnetic structures are important effects in local cosmic-ray propagation,
increasing the flux of cosmic rays by over two orders of magnitude at
anisotropic locations on the sky. The features induced by coherent magnetic
structure could be the cause of the observed TeV cosmic-ray anisotropy.
