Lohajung lies in the Chamoli district of Uttarakhand and is the base camp for several amazing treks here. This is why it has become quite easy to reach Lohajung nowadays, with plethora of transportation options to choose from.
The nearest airport to Lohajung is the Jolly Grant Airport in Dehradun which is approximately 293 km from Lohajung. So, you can take a flight to Dehradun and then you can hire a private cab, hire a shared taxi, or take a bus to reach Lohajung.
There is 1 bus every morning which leaves for Lohajung from Rishikesh and reaches around 5.30 p.m. However, this bus often stops at Deval which is 1 hour from Lohajung so you might need to hire a shared cab/private taxi from here to reach.
Kathgodam Railway station is the nearest railway to Lohajung at a distance of 220 km. And there are many trains coming here from several major cities so you can reach here first.
From here, you can take a shared taxi or a private cab to reach Lohajung.
If you know how to drive in hills then you can also take your own vehicle to reach Lohajung. There aren't many buses coming to Lohajung, except for 1 bus from Rishikesh but even that is not certain.
So, if you want to take the road route, you will have to start from Rishikesh then reach Karnaprayag. From Karnaprayag, you will need to find a shared taxi to Deval and from Deval, another shared taxi to Lohajung.