Disclosed are, inter alia, methods, apparatus, data structures, computer-readable media, mechanisms, and means for defining, creating and using tree bitmap data structures, such as for, but not limited to their use in performing lookup operations (e.g., longest prefix matching, etc.). The data structure typically includes a tree bitmap for identifying for each node of multiple nodes within a stride of a number of tree levels greater than one whether each node is a prefix or vacant node, the multiple nodes representing multiple tree levels, a lowest level subset of the multiple nodes corresponding to a lowest level of the tree levels in the stride, the lowest level subset of the multiple nodes including two or more nodes. A child bitmap is typically used for identifying which trie paths emanate and which trie paths do not emanate from the lowest level subset of the multiple nodes.