Lahan (लहान) is a city and municipality in the Siraha district of Madhesh, Nepal.

[3] and Government of India has set up a Land Customs Station with a Superintendent level officer.

The population has increased gradually due to urbanization over a period of 20 years.

Rajbiraj Airport is the nearest airport 43.1 km away from Lahan where daily 1 flight from Rajbiraj to the capital city Kathmandu is operated with the flight time of 35 minutes.

[6][7] The city is also connected to Laukaha Bazar railway station which is located in nearby Indian town of Laukaha, 18 km south via Nepali town of Thadi which is one of the main entry and exit point for people of Nepal and India.