Ever since I looked down the forbidden valley from Kagbeni while trekking the Annapurna Circuit, I’ve wanted to hike Lo Mustang in Nepal. Sadly, no independent hiking is allowed.
Kagbeni at 2810 m, spectacularly situated atop a cliff overlooking the confluence of the Kali Gandaki and the Jhong Khola rivers, is the last village in Lower Mustang and guards the entrance into Upper Mustang, visible across the Kali Gandaki riverbed. It is the northernmost village that can be visited without a permit to continue on to Mustang.
Northwards into Upper Mustang – larger photo on flickr – Claudia
Footprint Tours is one of the few companies who offer trekking trips:
… Until 1992 less than a dozen foreigners had been to Mustang. Now, in an effort to protect this culture, access is limited with less than 800 trekkers making the journey each year. The requirement to pay high restricted-area fees, travel with an organised group and take a Liaison Officer, together with difficult access continue to make the Kingdom of Lo an uncommon destination. …
A trek to the Himalayan kingdom of Mustang in the restricted regions of Nepal
That same site has a nice overview of Himalayan trekking for those who have never been:
In 1965 Colonel Jimmy Roberts introduced the world to trekking. As a former Gurkha Officer and Military Attaché at the British Embassy in Kathmandu he had spent years of his life walking the hills of Nepal. His idea, revolutionary for the time, was to provide tents together with Sherpas, to guide and cook.
This made Nepal and the Himalaya available to a wide community and was an immediate success.
Nowadays the formula is well established; groups travel through the hills, walking for five to six hours each day with all their equipment carried by porters or yaks; good quality meals are provided along with warm sleeping bags and comfortable tents; the trekker carries a personal pack with camera, day clothing and snacks. …
photo – Jimmy Roberts in 1996 a year before his death.
read more – What is Trekking?
At this rate, I may need to wait until independent hiking is allowed.
besthike.com 
“The Hidden Valley…”
I like the sound of that…
You have had some great treks!
DSD
I did the Annapurna Circuit in 1994 & I too looked up the valley from Kagbeni into Mustang. 9 years later in 2003 I came back & did the trek up to Lo Manthang and back. Truley amazing.
We did it independently without a liason officer & stayed mostly in tea houses en route. We did take a guide & we had to get a permit for $700 for 10 days.
Excellent.
I will be looking for a trip like that next time I get to Nepal.
You are one of the lucky few to have been there. Wow.
Let me know if you want any more info.
I will email you, Joe. And post your details on this blog for everyone else who might want to get to “Mustang”.