The Széchenyi Chain Bridge is an almost 170-years-old historical structure located in the downtown of Budapest. Its reconstruction was made between 2020 and 2022, when the deck system of the bridge is replaced by an orthotropic deck and the main girder is renewed. During the design the damages and the rotation of the pins between the eyebars in the chain system were questionable due to corrosion and friction. Therefore, the rotation capacity and the corrosion grade of the chain elements were investigated before and during the reconstruction process to clearly determine the structural health and further lifetime. Four on-site measurements were executed to analyse these issues: (i) loading test to measure the bending moments in the chains and checking the rotation of the pins, (ii) one-year-long monitoring system operating during the renewal process having the aim to check the bending moment distribution in the chain elements during the reconstruction process, (iii) chain element corrosion measurements and (iv) load test of the reconstructed bridge. The paper introduces the new design, the measurement results regarding the corrosion grade and the monitoring system data. The main conclusions of the measurements and accomplishing statistical evaluations are presented in the paper to evaluate the structural health to estimate the further lifetime of the bridge.