This work investigates the multiplicity distributions of emitted protons produced in proton–nucleus collisions involving carbon, oxygen, and sodium nuclei at momenta of 4.2, 8.4, and 12.6 GeV/c. The study is based on simulated data obtained using the Dub-na cascade-evaporation model. For each reaction, 10,000 events were analyzed. The results show that the proton multiplicity distributions exhibit three characteristic re-gions corresponding to the values: n ≈ 0–4, n ≈ 5–7, and n ≥ 8. We assume that the region n ≈ 0–4 corresponds to peripheral collisions, n ≈ 5–7 to semi-central collisions, and n ≥ 8 to central collisions. The results confirm that the degree of collision centrality is directly related to the number of emitted protons. In peripheral collisions, the interac-tion involves only the outer layers of the nucleus, resulting in a smaller number of emit-ted particles. In central collisions, by contrast, the interaction affects a larger portion of the nucleus, leading to a sharp increase in the number of emitted protons.