High-resolution near-infrared spectra of the nu(HCl)=1<--0 fundamental stretch in Ar2HCl and Ar3HCl have been characterized using a slit-jet infrared spectrometer. Analysis of the jet-cooled, rotationally resolved spectra (i) permits unambiguous identification of the cluster size, (ii) provides vibrationally averaged geometries in the nu(HCl)=1 excited state, and (iii) allows the vibrational shift of the HCl chromophore to be measured as a function of the number of Ar atoms in the complex. The equilibrium structures of ArnHCl (n=1-3) clusters calculated using accurate Ar-Ar and Ar-HCl pair potentials are consistent with the vibrationally averaged structures inferred spectroscopically. The vibrational red-shifts for ArnHCl (n=1-3) reflect a near-linear dependence on the number of Ar atoms, which is qualitatively reproduced by simple classical calculations on nu(HCl)=0 and 1 pairwise additive potential surfaces. Theoretical predictions of the ArnHCl red-shifts in a fee lattice indicate good agreement with experimental matrix results. However, to achieve this asymptotic limit requires up to n approximate to 54 Ar atoms; this underscores a clear sensitivity to non-nearest neighbor Ar-HCl interactions significantly outside the first solvation shell. Finally, for smaller ArnHCl clusters with only one solvation shell (n=12), the potentials predict an energetic preference for HCl in surface vs interior sites. Analysis indicates that this effect is predominantly due to Ar/HCl size mismatch, which destabilizes the nearest neighbor Ar shell for HCl solvated in the center of the cluster.