The Narrows were a place in the pass between Westland and the Midlands where the walls of the Boundary nearly touched each other. It was the most dangerous part of the pass. A step or two off to either side and one would have gone too far, as the walls of the boundary were that close.
The narrows were right in the middle of the pass, thus a traveler would reach it in the night. It was marked from Westland through a large boulder the size of a house. The rock was split half and one had to go through the rock to stay on the pass.
At it place of the boundary one would be able to here the things from the boundary call after you. One had to have a strong will otherwise one was lost forever in the Narrows.
When Kahlan and Richard reached the Narrows the path through it had been burrowed by a slide.