Magnetic force microscopy (MFM) has been employed to study thin films consisting of low-energy-deposited cobalt nanoclusters. On continuous cluster layers a clear magnetic stray field pattern can be observed, although measurements on individual clusters are complicated by interference from topography. The magnetic correlation length determined from MFM images is substantially larger than the size of a single cluster. This indicates that the clusters are magnetically coupled to form stable domains associated with the formation of a correlated super-spin-glass state. (C) 2004 American Institute of Physics.