The highway from Kaza to Gramphu remains closed for 6–9 months in a year due to heavy snowfall and the closure of Kunzum La pass at an elevation of 4,550 m (14,930 ft).

The road is narrow and rough at places and crosses the high-elevation Kunzum pass, requiring good driving skills in mountains.

[6] NH 505 has been of key importance to the growth of a cash crop economy, mass tourism, and the expansion of telecommunications in Spiti.

[1] The terminus at Khab, Kinnaur district is the preferred point of entry to the Spiti Valley which is located at an average elevation of 3,350 m (10,990 ft).

The highway passes through some unusual clay pillars[10] en route to Kaza, the largest town in the Spiti Valley.

[12] NH 505 continues on the right bank running through a flat, narrow valley in which the Spiti Rver has carved a gorge about 300 m (980 ft) deep.

From Kunzum pass, the highway descends through steep hairpin bends to Batal village on the left bank of the Chandra River.

[13] From Batal, NH 505 follows the left bank of the Chandra River, practically running on the riverbed in some places, as both sides of the narrow valley are very steep.

It climbs steeply and runs along the top of a cliff overlooking the Chandra River until the terminus at Gramphu (Gramphoo).