Security plays an important role in the ability to deploy and retrieve trustworthy data from a wireless sensor network. Location verification is an effective first line of defense against attacks which take advantage of a lack, or compromise, of location information. In this work, a probabilistic approach to location verification in dense sensor networks is proposed. The proposed Probabilistic Location Verification (PLV) algorithm leverages the probabilistic dependence of the number of hops a broadcast packet traverses to reach a destination and the Euclidean distance between source and destination. A small number of verifier nodes determine the plausibility of the claimed location, which is represented by a real number between zero and one. Using the calculated plausibility metric, it is possible to create arbitrary number of trust levels in the location claimed. Simulation studies verify that the proposed solution provides high performance in face of various types of attacks.