Although Lahaul and Spiti are usually taken as one unit, they are two different destinations. Starting from Manali towards Rohtang Pass and Leh, you arrive at a junction near Yari-Khoksar. From there, the eastbound road leads to Karcha, Spiti, Kaza, and, after a very long loop, bends southwards to merge into NH22 and continue far south to Shimla. The westwards route from Yari-Khoksar continues as NH21 to Lahaul, Keylong, a string of hairpin bends, and the More Plains, eventually reaching Ladakh and Leh.
The passes (Rohtang and Kunzum La)coming from Manali side are usually closed until mid-May, whereas Reckong Peo Pass coming from the Shimla side can usually be traversed year round.