Data sharing is one of the most popular applications that dominate 70% of data traffic on the Internet. This application has been penetrating wireless mobile networks with dramatic speed, which allows the sharing of data whenever and wherever. However, traditional client-server data sharing model suffers from single point failure and low-scalable transmission in a highly dense and dynamic scenario. MANET is a promising alternative structure for flexible and distributed data sharing. However, the topology-based flooding employed in MANETs for data routing and querying prevents the data sharing system from achieving high scalability and robustness. Building a DHT on a MANET reduces data query overhead, but the inconsistency between the overlay and the underlying topology degrade system's performance. Geographic routing based data sharing in MANETs reduces the data routing overhead. However, it has more requirements (e.g. GPS) on the nodes. This paper presents a locality-based distributed data sharing system (LORD) for mobility and congestion resilient data management. LORD consists of a DHT-based data index and retrieval protocol and a locality-aware region-based data routing protocol. It provides highly efficient, scalable and dynamism-resilient data sharing with low overhead. Moreover, it offers similarity data searching function. Theoretical analysis and simulation results show the superiority of LORD compared with other data sharing systems in terms of scalability, overhead and dynamism-resilience in a highly dense and dynamic MANET.