This work delves into the seismic assessment of masonry bridges through a detailed analysis of an existing triple-arched bridge. Firstly, the effectiveness of the nonlinear static analysis is evaluated by means of a comparison with a comprehensive set of 84 nonlinear dynamic analyses. Secondly, the choice of the control node on the finite element structural model is investigated, in order to understand its influence on the prediction of seismic capacity. Although the node located at the top level is usually considered to characterize the force–displacement response of common structures, such a choice is not suitable for the considered case-study. The node located at the level of the bridge’s centre of mass proves to be a better choice since it ensures a more reliable estimation of the seismic capacity. The critical discussion of the numerical analyses results gives useful indications towards an improved procedure for the seismic assessment of the considered structural typology.