In this work, we studied exciton states of azobenzene aggregates by means of first-principles calculations. In particular, we applied time-dependent long-range corrected density functional theory (TD-lc-DFT) and ab initio configuration interaction singles (CIS) to large clusters including up to 18 azobenzene molecules. The character of the exciton states was analyzed computing "fraction of transition density matrix" (FTDM) matrices allowing one to quantify exciton delocalization pattern and charge transfer contributions to electronic transitions. The brightest excitons of the studied aggregates are dominated by local excitations of monomers composing the aggregates. Moreover, for the investigated model clusters, these excitons are delocalized over the entire cluster (with exception of the TD-ωB97X-D calculation for 18b). The charge transfer (CT) contributions to the brightest transitions are small, decrease with increasing nearest neighbour distance, and are larger for TD-lc-DFT (specifically, ωB97X-D) than for CIS. The CT states appear earlier in TDlc-DFT spectra than in the CIS spectra. This leads to large differences in the brightest state labels at short intermolecular distances. Comparison of TD-lc-DFT/CIS results with point dipole model (PDM) calculations shows that PDM overestimates excitation energies and oscillator strengths in the present case. Moreover, we found that treating a periodic chain at the BSE/GW level of theory leads to a larger blue shift in comparison to the calculations on cluster models. Finally, it should be mentioned that the (de)localization of the exciton states is affected by conformational disorder, as was demonstrated for an azobenzene tetramer in our recent work. Ultimately, the photoinduced dynamics may lead to further changes in (de)localization and result in exciton transfer between monomers, as was reported very recently by Sangiogo Gil et al., based on surface hopping calculations employing an exciton model.