Culverts are vital components of earth embankments, allowing watercourses like streams and nallas to flow without disrupting natural water movement. They play a key role in managing floodwaters on either side of the embankment, helping to reduce water levels and mitigate flood risks. Culverts come in various shapes, including arch, slab, and box configurations, and can be constructed from materials such as masonry or reinforced concrete. Embedded within earth embankments, culverts are subjected to traffic loads similar to those on the road surface and must be designed to accommodate these loads. This paper focuses on the structural design and parametric analysis of RCC box culverts, both with and without cushions, using STAAD.Pro. Design parameters, such as size, invert level, and layout, are determined based on hydraulic requirements and site-specific conditions, with the cushion thickness varying according to the road profile at the culvert location. This study examines various load cases, including empty box, full box, and surcharge loads, while considering factors such as effective width, load dispersion through fill, impact factor, and earth pressure coefficient, in accordance with IRC codes. It provides a comprehensive discussion on code provisions, design considerations, and justifications for the structural design of RCC box culverts, ensuring they can withstand maximum bending moments and shear forces.