Kumardubi (also spelled Kumardhubi) is an industrial neighbourhood located within the Nirsa CD Block of Dhanbad district, in the Indian state of Jharkhand. Although widely recognized as a distinct industrial locality, Kumardubi is not identified as a separate place or mouza in the 2011 census; maps in the District Census Handbook of Dhanbad indicate that it may be included within Chirkunda.

Kumardubi is located on the eastern edge of Dhanbad district, close to the border with West Bengal. While the Damodar River flows along the southern boundary, the Barakar River flows along the east.

The region shown in the map is a part of the undulating uplands of the eastern coal belt bustling with coalmines.

BCCL operates Chanch/ Victoria Area partially within the region shown in the map. ECL operates Mugma Area fully within the region shown in the map.

The Panchet Dam on the Damodar river and Maithon Dam on the Barakar river, along their reservoirs, are prominent geographical features. The entire area falls under the Nirsa CD block, where approximately 69% of the population lives in rural areas and 31% in urban areas.

Owing to its proximity to the coalfields of Dhanbad and abundant fire clay deposits, Kumardubi has long been recognized as a major industrial hub in eastern India. Key sectors include:

The Kumardubi area is served by the Kumardubi railway station on the Asansol–Gaya section, which is a part of the Grand Chord, Howrah-Gaya-Delhi line and Howrah-Allahabad-Mumbai line. The station handles both passenger and freight traffic and has historically supported the movement of industrial goods, particularly metal castings and engineering products.

The area is also served by the Grand Trunk Road, now part of NH 19 (old numbering NH 2), running from Agra to Kolkata. This highway provides direct access to major cities like New Delhi, Varanasi, and Kolkata. Local transportation is primarily facilitated by auto rickshaws and private bus services.