  A superconducting thin film with uniform properties is the key to realize
nanowire superconducting single-photon detectors (SSPDs) with high performance
and high yield. To investigate the uniformity of NbN films, we introduce and
characterize simple detectors consisting of short nanowires with length ranging
from 100nm to 15{\mu}m. Our nanowires, contrary to meander SSPDs, allow probing
the homogeneity of NbN at the nanoscale. Experimental results, endorsed by a
microscopic model, show the strongly inhomogeneous nature of NbN films on the
sub-100nm scale.
