The nearest airport is Dehradun's Jolly Grant Airport (about 200 km from Uttarkashi). You can avail taxis and buses that are available from the airport. Gartang Gali is 110 km from Uttarkashi.
Rishikesh and Dehradun are the nearest railheads to Uttarkashi (about 200 km away). Taxis and buses are available at both these railway stations.