Kalimpong is a bustling and rapidly expanding, though still relatively small, bazaar town set among the rolling foothills and deep valleys of the Himalayan at an altitude of 1250m. It was once part of the lands belonging to the rajas of Sikkim, until the beginning of the 18th century when it was taken from them by the Bhutanese. In the 19th century it passed into the hands of the British and thus became part of West Bengal. It became a centre for Scottish missionary activity in the late 19th century, and Dr Graham's orphanage and school is still running today.
Kalimpong's attractions include three monasteries, a couple of solidly built churches, an excellent private library for the study of Tibetan and Himalayan language and culture, a sericulture, orchid nurseries and fine views over the surrounding countryside. Although not many travellers bother to visit Kalimpong, there's enough here to keep you occupied for a couple of days, and for the energetic there's some good trekking.
The most interesting part of a trip to Kalimpong is the journey there from Darjeeling via the Teesta River bridge. If you have no permit for Sikkim then the town is worth visiting just for the journey.