  We consider a hidden sector model of dark matter which is charged under a
hidden U(1)_X gauge symmetry. Kinetic mixing of U(1)_X with the Standard Model
hypercharge U(1)_Y is allowed to provide communication between the hidden
sector and the Standard Model sector. We present various limits on the kinetic
mixing parameter and the hidden gauge coupling constant coming from various low
energy observables, electroweak precision tests, and the right thermal relic
density of the dark matter. Saturating these constraints, we show that the
spin-independent elastic cross section of the dark matter off nucleons is
mostly below the current experimental limits, but within the future
sensitivity. Finally, we analyze the prospect of observing the hidden gauge
boson through its dimuon decay channel at hadron colliders.
