Nepal being a mountainous country is a home of innumerable trails known as The Great Himalayan Trails covering an extensive trail system that ranges from Humla and Darchula in the west to Kanchenjunga in the east. The diversity of trekking in Nepal is hardly found in any other regions of the world. Among the trekking and hiking areas, Everest, Langtang and the Annapurna regions are known as the popular trekking routes in Nepal. Some of these Himalayan trails such as those in Kanchenjunga, Makalu, Dolpo, and the far West are accessible only via flight and some others such as Langtang and Annapurna trails are also accessible by road transport. Nepal has six diverse vegetation zones ranging from Tropical areas below 1000m through sub tropical 100m-200m, lower temperate 1700m -2700 m, upper temperate zones from 2400 m to 3000 m, subalpine zones 3000 m – 4000 m and alpine zones range from 4000m to the snowline and above snowline lies Himalayan Tundra like wilderness. Each of these zones is well populated with an appropriate flora and fauna.
Trekking in Nepal today is completely different from that of the 1960s. The main trekking areas, National Parks and Conservation Areas accommodate lodges and teahouses where trekkers not only find food and accommodation but also have opportunities to meet other trekkers and locals. The majority of the trails are well maintained and in many cases are sign-posted. The lodges have facilities for charging batteries and the larger villages often have email facilities. Although the popular treks in Kanchenjunga, Everest, Manaslu and Annapurna provide accommodation, the less frequented treks even in those areas and in other areas west of Annapurna will generally require camping support. Trekkers can find a trail for any time of year. The southern areas of Nepal receive higher levels of precipitation. However, some routes along the Great Himalayan Trails lie in the rain shadow, a dry area on the leeward side of a mountains namely Mustang to the north of Annapurna and Manaslu, Dolpo to the north of Dhaulagiri and the far west of Nepal to the north of Saipal Himal. Post monsoon the weather tends to be clearer. Winter is good but colder with shorter days and spring can be affected by seasonal rain and snow storms. Summer is short and is quickly followed by the monsoons.
The length, the difficulty and timing of the treks vary greatly and therefore transportation becomes a problem and often involves at least two journeys made on domestic scheduled flights. Domestic flights are generally scheduled early in the morning. In case two domestic flights are required, appropriate timing should be allowed from your part. The majority of visitors to Nepal come via Tribhuvan International Airport in Kathmandu. It is in Kathmandu that trekkers need to acquire their permits and other documentation, either from a trekking agent or from the appropriate offices. These documents will be checked along the trekking route. For those with little time to spend in Nepal, there are half-day hikes from Kathmandu to witness breathtaking Himalayan views. The treks over stunning Himalayas and challenging mountain passes consume a week or more for completion.
Up to the mid 1960s only a few trekkers had generally visited Nepal and back then as part of groups of expedition followers. Many of the big expeditions of the day encouraged trekkers to sign up in an attempt to help balance the funding.