Methods and apparatus are disclosed for longest common prefix based caching. An information space is partitioned into multiple subsets such that a particular subset including a particular prefix also includes all longer prefixes beginning with the particular prefix in the information space. A primary control unit typically maintains the information space and all of the subsets, and selectively distributes some or all of the subsets to basic control units, and each of basic control units does not necessarily receive the same group of subsets. In addition, the group of subsets maintained by a particular basic control unit may change during operation, typically to increase the likelihood that a particular basic control unit will contain the needed subset. When a particular basic control unit does not have the needed subset, it typically sends to the primary control unit, a request for a lookup result, for the primary control unit to process the packet or other information, or for the primary control unit to send the corresponding subset.