  We compute the properties of dark matter halos with mass $10^{6.5}-10^9\msun$
at redshift $z=6-11$ in the standard cold dark matter cosmological model,
utilizing a very high resolution N-body simulation. We find that dark matter
halos in these mass and redshift ranges are significantly biased over matter
with a bias factor in the range 2-6. The dark matter halo mass function
displays a slope of $2.05\pm 0.15$ at the small mass end. We do not find a
universal dark matter density profile. Instead, we find a significant
dependence of the central density profile of dark matter halos on halo mass and
epoch with $\alpha_0=0.4-1.0$; the high-mass ($M\ge 10^8\msun$) low-redshift
($z\sim 6$) halos occupy the high end of the range and low-mass ($M\sim
10^{7}\msun$) high-redshift ($z\sim 11$) halos occupy the low end.
Additionally, for fixed mass and epoch there is a significant dispersion in
$\alpha_0$ due to the stochastic assembly of halos. Our results fit a
relationship of the form
$\alpha_0=0.75((1+z)/7.0)^{-1.25}(M/10^7\msun)^{0.11(1+z)/7.0}$ with a
dispersion about this fit of $\pm 0.5$ and no systematic dependence of variance
correlated with environment. The median spin parameter of dark matter halos is
$0.03-0.04$ but with a large lognormal dispersion of $\sim 0.4$. Various
quantities are tabulated or fitted with empirical formulae.
