The Gap of Dunloe is a narrow mountain pass forged between the MacGillycuddy Reeks and Purple Mountain by glacial flows. The river running through the gap is the river Loe from where the Gap gets its name. The Gap begins at Kate Kearney's Cottage. The road, narrow in many places, winds through the pass and descends into The Black Valley passing five lakes, Coosaun Lough, Black Lake, Cushnavally Lake, Auger Lake, and Black Lough. Within easy walking distance from Kate Kearney's cottage is a picturesque old bridge known as the 'Wishing Bridge'. It is said that wishes made here really do come true!

The Gap is approximately 11 km from north to south. You can hire a jaunting car (horse-drawn wagon) to travel through the Pass and take a boat back to Killarney from Lord Brandon's cottage at the other end. It makes a good challenging day's exercise by bicycle. You could travel the opposite direction by taking a boat ride from Ross Castle in Killarney with your bike to Lord Brandon's Cottage and cycle back through the Gap to Kate Kearney's cottage.