The Marnadal Stairs is the name of a valley which leads south between the mountains of Amell and Erlenwald. The location is famous for the Battle of Marnadal in which the king of Cintra, Eist Tuirseach was killed. The stream which flows through the valley is also called "Marnadal".
|“||To take Cintra back from the Nilfgaardians. Let us cross the Yaruga, be the first to attack. Now, while they don't expect it. Let us throw them out, back beyond the Marnadal.||”|
— pg(s). 220, Blood of Elves (UK edition)
|“||'That is true,' nodded Demawend. 'Crach swore bloody vengeance on Nilfgaard. For Eist Tuirseach, killed at Marnadal. And for Calanthe. If we were to strike at the left bank, Crach would back us up with all the might of Skellige. By the gods, this has a chance at success! I back Foltest! Let us not wait, let us strike first, let us liberate Cintra and chase those sons-of-bitches beyond the Amell pass!'||”|
— pg(s). 221, Blood of Elves (UK edition)