The Noguera de Tor drains the Vall de Boí through limestone country in Alta Ribagorça — a valley more famous for its Romanesque churches than its trout fishing, which suits the trout fishing very well. Cold mountain water, alkaline from the limestone, with the productive character that chalk-influenced rivers have at altitude. Wild brown trout throughout, less pressured than the more accessible Catalan rivers. The Vall de Boí is beautiful enough to justify the drive regardless of the fishing; the fishing is a reason to stay longer than you planned.
- Limestone