Ghose and Desai [1] introduced a new interconnection for large-scale distributed memory multiprocessors called the Hierarchical Cubic Network (HCN). The HCN is topologically superior to a comparable hypercube. They also proposed optimal routing algorithms for the HCN and obtained its diameter, which is about three-fourths the diameter of a comparable hypercube. However. their routing algorithm is not distance-optimal. In this paper, we propose an optimal routing algorithm for the HCN and show that HCN has about two-thirds the diameter of a comparable hypercube.