The topography of Karimganj city is largely a low-lying alluvial plain, gently undulating in parts, with an average elevation of just 13 meters (42 feet) above sea level. The landscape is defined by the winding course of the Kushiyara River along its western and northern edges.
While the city itself is primarily flat, the surrounding areas feature small, scattered hillocks locally known as 'tillas'. These tillas are often utilized for tea plantations or human settlement to avoid floodwaters. The low elevation and flat terrain create extensive floodplains, which are highly fertile but require careful water management during the heavy rains of the monsoon months. There are no major mountain peaks within the city limits, but the distant hills of the Barail Range and the uplands of neighboring Mizoram and Tripura create a scenic backdrop.