The map of Elden Ring: Shadow of the Erdtree is vast and expansive, with an impressively diverse range of biomes to explore. One of these is Jagged Peak, a forbidding mountain that towers over the Land of Shadow. You can get there soon after starting the expansion, but only if you know where to look.
Elden Ring: Shadow of the Erdtree – How to get to Jagged Peak (Southern Mountain Region)
To reach Jagged Peak in Elden Ring: Shadow of the Erdtree, you'll need to go through the optional Dragon's Pit mini-dungeon in the southern part of Gravesite Plain. You can head here once you start the expansion if you wish. To get there, cross Ellac Greatbridge and head right, toward the gigantic Suppressing Pillar towering ahead of you.
The entrance to Dragon's Pit is in the cliff face just northwest of the Suppressing Pillar. It's a fairly straightforward dungeon, and if you've made it this far into Elden Ring you'll have no trouble. Defeat the Ancient Dragon-Man boss at the bottom, and you'll emerge in a new area of Gravesite Plain below where you were before.
There are two ways to go: east to the Foot of the Jagged Peak or south to the Grand Altar of Dragon Communion. I recommend visiting the Grand Altar before you begin your ascent of Jagged Peak. There is an interesting NPC there that you might want to meet, especially if you want to unlock Dragon Form in Shadow of the Erdtree.