Jomsom (2,713m) is the main town in the Mustang district and the gateway to the restricted Upper Mustang area. It sits on the flat floor of the Kali Gandaki valley, which at this altitude is arid and windswept — a complete contrast to the green terraces of the southern circuit. The town has an airstrip with daily flights to Pokhara (25 minutes, weather permitting), making it possible to fly out after completing the circuit rather than walking back.
Most Annapurna Circuit trekkers pass through Jomsom after descending from Muktinath, heading south towards Tatopani and Poon Hill. A side trip north to Kagbeni (2,807m) — a walled medieval village at the junction of the Kali Gandaki and the restricted Mustang valley — is worth the extra half-day. Kagbeni's alleyways and wind-worn gompa give a strong taste of the Tibetan Buddhist culture that deepens further into Mustang. The Thak Khola Hotel in Kagbeni is said to pour the best apple brandy in the district.
Jomsom itself has a strip of teahouses and trekking lodges along its main street, plus the Mustang Eco-Museum, which covers the geology and culture of the region well. Flights are unreliable and frequently cancelled due to wind; plan flexibility into your schedule if flying rather than walking.