  We prove a new, large family of area laws in general relativity, which apply
to certain classes of untrapped surfaces that we dub generalized holographic
screens. Our family of area laws contains, as special cases, the area laws for
marginally-trapped surfaces (holographic screens) and the event horizon
(Hawking's area theorem). In addition to these results in general relativity,
we show that in the context of holography the geometry of a generalized
holographic screen is related to the outer entropy of the screen. Specifically,
we show for spherically-symmetric spacetimes that the area of the largest HRT
surface consistent with the outer wedge can be computed in terms of the
geometry of the general (not necessarily marginally-trapped) codimension-two
surface defining the wedge. This outer entropy satisfies a second law of
thermodynamics, growing monotonically along the generalized holographic screen.
In particular, this result provides the holographic dual for the geometry of
the event horizon for spherically-symmetric spacetimes.
