We consider the analogue of Hurwitz curves, smooth projective curves C of genus g ≥ 2 that realize equality in the Hurwitz bound | Aut(C)| ≤ 84(g − 1), to smooth compact quotients S of the unit ball in C 2 . When S is arithmetic, we show that | Aut(S)| ≤ 288e(S), where e(S) is the (topological) Euler characteristic, and in the case of equality show that S is a regular cover of a particular Deligne-Mostow orbifold. We conjecture that this inequality holds independent of arithmeticity, and note that work of Xiao makes progress on this conjecture and implies the best-known lower bound for the volume of a complex hyperbolic 2-orbifold.Let M be a closed Riemannian manifold of negative sectional curvature and M be its universal cover. Then Aut(M ) is well-known to be finite and O = M/ Aut(M ) is a Riemannian orbifold with universal cover M , that is, there is a