We present the Cooperative Location-sensing system (CLS), an adaptive location-sensing system that enables devices to estimate their position in a self-organizing manner without the need for an extensive infrastructure or training. Hosts cooperate and share positioning information. CLS uses a grid representation that allows an easy incorporation of external information to improve the accuracy of the position estimation. We evaluated the performance of CLS via simulation and investigated the impact of the density of landmarks, degree of connectivity, range error, and grid resolution on the accuracy. We found that the average error is less than 2% of the transmission range, when used in a terrain with 20% of the hosts to be landmarks, average network connectivity above 7, and distance estimation error equal to 5% of the transmission range.