<p>Bihar, an Indian state located in seismic zones III, IV, and V, has experienced severe earthquakes in the past. Due to the presence of alluvium soil deposits over the bedrock in the Bihar region, seismic waves near the ground surface can amplify and cause catastrophic damage to existing structures. Therefore, to ensure the safety of the structures, it is imperative to assess the amplification level of seismic waves near the surface. This study presents a new empirical correlation for the site classes C, D, and E of the Bihar region, which estimates the spectral acceleration (<i>S</i>_<i>a</i>) at the required time period. These site classes of the Bihar region refer to the classification of soil and geological conditions based on their behaviour during seismic events, specifically their impact on seismic wave amplification, ground shaking, and overall earthquake hazard, as per NEHRP classification. The results of this investigation can be applied to enhance the seismic design of structures and, hence, mitigate the seismic risk. Moreover, the developed empirical correlation for <i>S</i>_<i>a</i> can be used to estimate the design spectrum acceleration at the surface level for site classes C, D, and E of the Bihar region.</p>