Highway bridges are crucial elements of essential infrastructure, enabling continuous transportation, emergency response, and evacuation routes, particularly in seismic-prone regions. Despite significant progress in understanding the seismic behavior of concrete bridges, the impact of irregularity on bridge failure remains a notable concern. This study conducts a comprehensive literature review of reinforced concrete (RC) bridge structures that failed due to diverse irregularities, encompassing both structural and geometrical factors, under seismic conditions. The literature review incorporates historical data of bridge failures attributed to seismic events, with a specific focus on cases where irregular span and geometry arrangements were identified as contributing factors. This review provides insights into how these irregularities influence the seismic performance of bridge structures, ultimately contributing to overall sustainability and performance enhancement. The study aims to assist designers and policymakers in determining the permissible extent of various types of irregularities. By clarifying the relationship between various irregularities and recorded bridge failure cases, this study contributes to the development of guidelines and strategies for mitigating seismic risks in bridge design and construction. Ultimately, the findings of this study have practical implications for enhancing the resilience and safety of highway bridges in seismic-prone regions.