  We use neutron scattering to demonstrate the presence of lattice polarons and
their short-range correlations for several samples of La$_{1-x}$Ca$_x$MnO$_3$
in the Ca doping range $0.15\leq x\leq 0.3$. We establish the doping dependence
of the orientation, commensuration, and coherence length of the polaron
correlations and show that the populations of correlated and uncorrelated
polarons are intimately related to the transport properties of the materials.
