  Unlike three-dimensional Einstein gravity, three-dimensional massive gravity
admits asymptotically de Sitter space (dS) black hole solutions. These black
holes present interesting features and provide us with toy models to study the
dS/CFT correspondence. A remarkable property of these black holes is that they
are always in thermal equilibrium with the cosmological horizon of the space
that hosts them. This invites us to study the thermodynamics of these solutions
within the context of dS/CFT. We study the asymptotic symmetry group of the
theory and find that it indeed coincides with the local two-dimensional
conformal algebra. The charge algebra associated to the asymptotic Killing
vectors consists of two copies of the Virasoro algebra with non-vanishing
central extension. We compute the mass and angular momentum of the dS black
holes and verify that a naive application of Cardy's formula exactly reproduces
the entropy of both the black hole and the cosmological horizon. By adapting
the holographic renormalization techniques to the case of dS space, we define
the boundary stress tensor of the dual Euclidean conformal field theory.
