This species is found in a variety of habitats, primarily in pristine forests, but it can also be found in degraded forest, mangrove swamps and even agricultural areas with remnants of woodland. It has also been found swimming in rivers in non-forested land and probably occurs in palm oil plantations (R. Inger pers. comm. 2010), however it is not yet clear whether oil palm plantations can support viable populations of this species (M. Auliya pers. comm. 2011). In India, this species has also been recorded from tea estates in the Western Ghats and Assam (Whitaker and Captain 2004). In Nepal this species is poorly-known, but has been reported primarily from undisturbed Sai forest and from dry high-altitude grasslands (D. Jelić pers. comm. 2012). Females build nests of dead leaves and stay with the eggs until they hatch, which takes 70 days at 28²C (Whitaker and Captain 2004). Reproductive age in captivity has been estimated at 5-6 years, and this is here conservatively taken to be the generation length in the wild population, although true generation length is probably longer. One individual was reported to have a 6.3 km² home range (Bhaisare et al. 2010), indicating that the species is likely to occur in low population densities, although it is unknown whether this is natural or a result of the depletion of wild populations.

The King Cobra is widely distributed in South and Southeast Asia, from Nepal (where it is found throughout the lowlands of the Therai region - Schleich and Kästle 2002) and India (from Uttarakhand in Western Himalayas to Eastern Himalayas, down south along the Eastern Ghats up to northern Andhra Pradesh, and in the Western Ghats south of Maharashtra) across southern China (including Hainan Island), southward to the Philippines (where it is widespread) and Indonesia east as far as Sulawesi and Bali (where there are recent records from Negara [R.P.H. Lilley pers. obs. 2011]; Smith 1943, Zhao and Adler 1993, David and Vogel 1996, Whitaker and Captain 2004), as well as the Malaysian territories of Sarawak and Sabah, and Brunei (where a recent record exists from Kuala Belalong Field Centre - J.M. Dehling unpubl. data), on the island of Borneo. It occurs in the Andaman and Nicobar Islands, but is absent from Little Andaman and from the Mentawai Islands off Sumatra. It has a maximum recorded elevation of 2,000 m asl. (Smith 1943).

The species is listed in CITES Appendix II. This species has been regionally assessed in India, China and Vietnam. The Regional India preliminary assessment of Near Threatened was made by the BCPP CAMP, while in China it was assessed as Critically Endangered in the national Red Data Book, and as Endangered in the China Species Red List (Wang and Xie 2009). It is listed as Critically Endangered in the national Red Data Book for Viet Nam (Dang et al. 2007), where it is a protected species. There are protected areas within the range of this species which probably provide small safeguards from harvesting pressure. Conservation measures are required to reduce the rate of habitat destruction occurring within its range and to manage the trade levels of this species. Further research into, and monitoring of the population status of, this species is required, as well as research into sustainable harvesting levels. Taxonomic research is also needed to determine if this species actually consists of a complex of species. Educational programmes may help to minimise the persecution of the species. In Royal Chitwan National Park the King Cobra is included in a new project focusing on ecological monitoring of and providing education about large reptiles, run by Nepal's National Trust for Nature Protection, the park authority, and the Zoological Society of London (D. Jelić pers. comm. 2012).