  We study the mechanics of D-dimensional isolated horizons (IHs) for Einstein
gravity in the presence of arbitrary p-form matter fields. This generalizes the
analysis of Copsey and Horowitz to non-stationary spacetimes and therefore the
local first law to include non-monopolar (dipole) charges. The only requirement
for the local first law to hold is that the action has to be differentiable.
The resulting conserved charges are all intrinsic to the horizon and are
independent of the topology of the horizon cross sections. We explicitly
calculate the local charges for five-dimensional black holes and black rings
that are relevant within the context of superstring theory. We conclude with
some comments on the black-hole/string correspondence principle and argue that
IHs (or some other quasilocal variant) should play a fundamental role in
superstring theory.
