The Katihar–Siliguri line is a railway line connecting Katihar in the Indian state of Bihar with Siliguri Junction in West Bengal, via Barsoi, Dalkhola, Kishanganj, Aluabari Road Junction, Thakurganj, Adhikari, Naxalbari, Bagdogra and Matigara.

Another railway line with a slightly different route with shorter distance exists between Siliguri Junction and Aluabari Road Junction (Islampur) and its details are available in Howrah–New Jalpaiguri line article.

Siliguri was connected to Calcutta (now spelt as Kolkata) via the eastern part of Bengal since 1878 (for details see Howrah–New Jalpaiguri line).

[1] A generally acceptable route to Siliguri was via Sahibganj loop to Sakrigali ghat.

[1] In the sixties, new 5 ft 6 in (1,676 mm) broad gauge lines were laid in the area and in 1971 with the rail bridge over Farakka Barrage, Siliguri was once again directly connected with Calcutta (now spelt as Kolkata) by 576 kilometres (358 mi) long broad-gauge track.

[1] An Indian Railways Fan Club enthusiast reported (in June 2005): "Near Siliguri, a MG line emerges to the right, on a somewhat high embankment and continues to run parallel to the road.