One of the most salient features of wireless communications is that users can deploy a variety of wireless devices to communicate with others, regardless of their locations. Although mobility support provides flexibility and convenience, it introduces many challenging issues to network design, planning, and performance evaluation. With the increasing demand for multimedia applications, location-aware services, and system capacity, many recognize that modeling and management of location and mobility are becoming critical to locating mobile objects in wireless information networks. Location management and mobility modeling strongly influence the choice and performance of mobility and resource management algorithms, such as routing, handoff, and call admission control in many types of wireless networks. For these reasons, it is important to understand mobility modeling and location management mechanisms and the manner in which these mechanisms depend on the characteristics of mobile environments. This article is concerned with issues in, and methods for, location management and mobility modeling in wireless data networks. The most distinguished features of next generation wireless systems can be highlighted as reliable quality of service (QoS) for various applications and global roaming. Since the intrinsic characteristic of mobile communications is mobility support, wireless systems must be able to locate roaming mobile terminals (MTs) at any time to deliver services and to maintain connections, as the MTs move from one service area to another. Location management techniques enable mobile users to move around, even between different systems with dissimilar signaling formats and protocols, while simultaneously offering them incoming calls and maintaining services in progress. Therefore, the objective of mobility modeling is to estimate the current and future locations of a mobile user upon the arrival of a connection request, which involves many parameters, such as moving speed, call duration time, distance between the last known position and destination, and geographical conditions. Location management, however, deals with the problem of how to register or update new location of a mobile user with a wireless system, and how to locate a mobile terminal given the information in system databases.