The most popular trail in Spain's largest protected natural area. The route follows the Borosa river through a spectacular gorge, passing the Nacimiento del Aguas Negras spring, through two long tunnels (torch required), to emerge at the high-altitude Valdeazores and Aguas Negras lakes — stunning in all seasons.
The Borosa River Trail is the most popular walking route in the Parque Natural Sierras de Cazorla, Segura y Las Villas — Spain's largest protected natural area, covering over 209,000 hectares of mountain wilderness in Jaén province in northern Andalusia. The trail follows the Borosa river upstream for the full 21-kilometre round trip from the Torre del Vinagre visitor centre to the remote Valdeazores and Aguas Negras lakes, gaining 700 metres over the route.
The trailhead is at the Torre del Vinagre visitor centre, approximately 25 kilometres from Cazorla town via the A-319 road. A car is effectively essential as public transport to the trailhead is extremely limited; the drive from Cazorla takes around 45 minutes through spectacular mountain scenery. The visitor centre has toilets, a café, and a small museum on the park's natural history — worth visiting before the walk.
From the visitor centre, the trail follows the Borosa river gorge upstream on a well-maintained rocky path. The first 5 kilometres are the most accessible, following the riverside through mixed pine and oak forest with clear river views and several stepping-stone crossings. The route then enters the Borosa gorge proper, where the path becomes rockier and the cliffs close in dramatically above the river. Two long tunnels bored through the limestone cliff walls — each running 100-200 metres — must be negotiated with a headlamp torch. Without adequate lighting, these sections are genuinely dark and treacherous; a dedicated headlamp is not optional.
Emerging from the tunnels, the trail continues through high mountain terrain to the Nacimiento del Aguas Negras — a spectacular spring where the river emerges directly from the cliff face. The final push to the Valdeazores lake (the main turnaround point) offers an excellent alpine setting for a lunch stop and is a popular swimming destination in summer.
Wildlife is outstanding throughout the route — red deer are commonly seen in the river valley, mouflon inhabit the rocky upper sections, and Spanish ibex are occasionally spotted on the cliff faces. In October, the red deer rutting season fills the valley with the sound of stags calling from dawn, making this the most atmospheric month for the trail.
Trail facts
- Trail area
- Parque Natural Sierras de Cazorla, Segura y Las Villas
- Best season
- May-June, September-October
- Terrain
- Rocky river-side path, some water crossings, tunnels, good gradient
Highlights
- Borosa river gorge
- Two walk-through tunnels (torch essential)
- Aguas Negras spring
- Valdeazores lake (excellent swimming)
- Red deer and mouflon wildlife
Tips for visiting
- Carry a dedicated headlamp — not a mobile phone torch — for the two tunnels; the longer tunnel runs approximately 200 metres in complete darkness with an uneven rocky floor and a phone torch leaves one hand unavailable for balance.
- Start no later than 8 AM from the Torre del Vinagre car park; the 21-kilometre round trip requires 6-7 hours and afternoon light fades early in the deep valley from September onwards.
- Visit in October for the red deer rut — stags can be heard calling from dawn and are frequently visible in the open river valley in early morning before other hikers arrive.
- The trail is at its most beautiful in May and June when the river runs strong from snowmelt and the surrounding forest is at its freshest; the lake provides excellent swimming by late June.
- Book accommodation in Cazorla town at least 2-3 days in advance in spring and autumn — the town has limited hotel capacity and fills during the peak hiking season.
When to visit
May to June and September to October are the best months for the Borosa trail — spring brings strong river flow and fresh forest colour, while October offers the red deer rut, one of the most spectacular wildlife events in Andalusia. July and August are viable but hot; the lake provides welcome swimming at the turnaround point.
Accessibility
The Borosa River Trail is not accessible to wheelchair or stroller users. The route involves 21 kilometres of rocky mountain path, river crossings, steep gorge terrain, and two dark tunnels requiring hands-free navigation. The first kilometre from the visitor centre along flat riverside path may be partially passable with a robust stroller, but the gorge and tunnel sections are entirely unsuitable for mobility aids.
Frequently asked questions
Is a headlamp really necessary, or will a phone work?
A dedicated headlamp is strongly recommended. The longer tunnel is approximately 200 metres of complete darkness with an uneven rocky floor. A phone torch leaves one hand occupied and may deplete the battery needed for navigation; a headlamp keeps both hands free throughout.
Can I do just the gorge section without going all the way to the lake?
Yes — the gorge and tunnels section (approximately 10 kilometres round trip from the visitor centre) makes an excellent shorter hike covering the most dramatic scenery. The lake adds around 11 kilometres and 400 metres of additional elevation for those with full-day capacity.
Is the Borosa trailhead accessible by public transport?
Public transport to the Torre del Vinagre visitor centre is very limited. Most visitors arrive by car from Cazorla town (45 minutes) or Jaén city (around 2 hours). Taxi services from Cazorla can be arranged but should be pre-booked, particularly in peak season.
What wildlife can be expected on the trail?
Red deer are reliably seen throughout the year, most frequently in early morning. Mouflon inhabit the upper rocky sections. Golden eagles, griffon vultures, and peregrine falcons are regularly seen overhead. October is the best month for wildlife overall — the red deer rut creates exceptional sighting and listening opportunities from dawn.