Provided are a method, system, and program maintaining and using nexus information on a host, port and device connection. A login is received from a host port on a storage controller port, wherein the host port has been configured on the storage controller to access one or more devices. An entry is added to a host-storage controller ports data structure for the host port and storage controller port involved in the login. At least one pointer is initialized in the entry in the host-storage controller ports data structure to point to at least one entry in at least one intermediate data structure. One pointer is initialized in each entry in one intermediate data structure addressed by one initialized pointer in the host-storage controller ports data structure to point to a nexi data structure having a plurality of entries.