The two main trail centres in the Lake District are Grizedale in the South of the Lakes and Whinlatter in the North.

Overview

The terrain is rocky, rooty and full of natural singletrack There is a large network of bridleways (100's of kilometers).

Check out the downloadable GPS routes in the GPS and Region Tabs on this listing. Brief description of what's available below:
The Southern Lakes which is rocky has trails which you can find in the GPS tab like Loughrigg Fell, Grizedale Parkamoor, Parkamoor Claife Heights and Walna Scar.
The Eastern Lakes has famous tracks like Ullswater, Helvellyn, Helvellyn - Sticks Pass, High Street to Hell, Staveley and the Garburn Pass, Staveley and the Nan Bield Pass, Staveley - Three Passes and The Garburn Pass.
There is also the Northern Lakes with tracks around Skiddaw.

This site lists routes for all ability levels in a bite-sized chunk format so you can piece routes together. They grade everything by either Easy, Moderate, or Hard and there are approximately 40 routes to choose from. It is neatly laid out with the description, turn by turn instructions, map guides, and GPX. They also cover the Yorkshire Dales, North Yorks Moors, Lancashire and Northumberland.

This site has around 13 trail guides. Each one has a description, turn by turn detailed descriptions, ability gradings and you can download the GPX file. It doesn't just cover the Yorkshire Dales MTB scene but it also has guides across other neighbouring areas and beyond.

Clubs and Groups

If you have ridden the MTB trails in the Lake District then please share your pictures, reviews, tracks and videos on the listing.