The $n$-dimensional Manhattan network $M_n$---a special case of $n$-regular digraph---is formally defined and some of its structural properties are studied. In particular, it is shown that $M_n$ is a Cayley digraph, which can be seen as a subgroup of the $n$-dim version of the wallpaper group $pgg$. These results induce a useful new presentation of $M_n$, which can be applied to design a (shortest-path) local routing algorithm and to study some other metric properties. Also it is shown that the $n$-dim Manhattan networks are Hamiltonian and, in the standard case (that is, dimension two), they can be decomposed in two arc-disjoint Hamiltonian cycles. Finally, some results on the connectivity and distance-related parameters of $M_n$, such as the distribution of the node  distances and the diameter are presented.