Katihar is a major railway station under North-East Frontier Railway. It is a very old station. In fact Katihar junction is a five (Eight if local lines taken together) line junction. 1st line goes to Barauni, 2nd line to Kolkata, 3rd line to Jogbani (Nepal border), 4th line to Guwahati, 5th line to Manihari. The other three local lines go to Purana Jute Mill, Naya Jute Mill and FCI. Katihar is also the headquarters of Katihar Railway Division. The major station under this division includes New Jalpaiguri, Siliguri, Darjeeling, Kishanganj etc. The world heritage Darjeeling Himalayan Railway falls under the jurisdiction of Katihar Railway Division. One can find trains to Nepal and Bangladesh border from here. In fact pre independence this station was connected with present day Bangladesh. All the trains passing through Katihar stops here. One can get a direct train to most of the Indian cities from this station. The notable trains are Rajdhani Express, Capital Express, Avadh Assam Express, North-East Express, Dadar Express, Amprapali Express, Sikkim Mahananda Express, Amarnath Express, Hate Bazare Express, Bangalore Express etc. Due to lack of poor road network train communication is the only source of communication.
The town does not fall on the national highway. However, NH-31 passes through the District and it is not far from Katihar Town. The road connectivity is not so good. Bus service is mostly limited to Purnea, Siliguri, Jogbani, Manihari, Bhagalpur etc. The nearest commercial airport is Bagdogra (190 km). There is an old time airstrip in the town which is mostly used as a helipad. The place is known as Hawai Adda.
Katihar is a Telecom District headed by General Manager Telecom, BSNL which covers the areas of Purnea, Kishanganj, Fobesganj, Araria, etc. Airtel, RTL, Aircel, Tata, Reliance Infocomm are the other private players giving telecom services. The teledensity is low especially in rural area which reflects the economic backwardness of the rural area.