Symmetric key agreement is significant to security provisioning in sensor networks with resource limitations. A number of pairwise key pre-distribution protocols have been proposed, but their scalability is often constrained by the conflict between the desired probability of sharing keys between neighboring nodes and the resilience against node capture attacks under a given budget for storing keying information within each sensor. In this paper, we propose LKE, a self-configuring in-situ key establishment scheme targeting large-scale sensor networks. LKE employs location information for a deterministic key space generation and keying information distribution. For uniformly distributed networks, LKE exhibits strong resilience against node capture attacks and achieves a high key-sharing probability (close to 1) at the expense of a small amount of memory overhead. An improvement over LKE, termed as iLKE, is also proposed. iLKE is topology-adaptive, and therefore works well for both unifor...