We present a proposal for the full phase space distribution of the Milky Way halo . The model is axially and reflection symmetric and its time evolution is self-similar . It describes the halo as a set of discrete dark matter flows with stated densities and velocity vectors everywhere . We first discuss the general conditions under which the time evolution of a cold collisionless self-gravitating fluid is self-similar , and show that symmetry is not necessary for self-similarity . When spherical symmetry is imposed , the model is the same as described by Fillmore and Goldreich , and by Bertschinger , twenty-three years ago . The spherically symmetric model depends on one dimensionless parameter \epsilon and two dimensionful parameters . We set \epsilon = 0.3 , a value consistent with the slope of the power spectrum of density perturbations on galactic scales . The dimensionful parameters are determined by the Galactic rotation velocity ( 220 km/s ) at the position of the Sun and by the age of the Galaxy ( 13.7 Gyr ) . The properties of the outer caustics are derived in the spherically symmetric model . The structure of the inner halo depends on the angular momentum distribution of the dark matter particles . We assume that distribution to be axial and reflection symmetric , and dominated by net overall rotation . The inner caustics are rings whose radii are determined in terms of a single additional parameter j _ { max } . We summarize the observational evidence in support of the model . The evidence is consistent with j _ { max } = 0.18 in Concordance Cosmology , equivalent to j _ { max,old } = 0.26 in Einstein - de Sitter cosmology . We give formulas to estimate the flow densities and velocity vectors anywhere in the Milky Way halo . The properties of the first forty flows at the location of the Earth are listed .