  Generalizations of the Black Hole geometry of Ba\~nados, Teitelboim and
Zanelli (BTZ) are presented. The theory is three-dimensional vacuum Einstein
theory with a negative cosmological constant. The $n$-black-hole solution has
$n$ asymptotically anti-de Sitter ``exterior" regions that join in one
``interior" region. The geometry of each exterior region is identical to that
of a BTZ geometry; in particular, each contains a black hole horizon that
surrounds (as judged from that exterior) all the other horizons. The interior
region acts as a closed universe containing $n$ black holes. The initial state
and its time development are discussed in some detail for the simple case when
the angular momentum parameters of all the black holes vanish. A procedure to
construct $n$ black holes with angular momentum (for $n \geq 4$) is also given.
