Gran Trail de Peñalara 104km — 5,100m D+, a 23:30 Night Start, and Peñalara Summit (2,430m) Above Madrid in the Sierra de Guadarrama

Gran Trail de Peñalara (GTP) is a 104km circular mountain ultra organized by RSEA Peñalara (Real Sociedad Española de Alpinismo Peñalara), the historic Spanish mountaineering club founded in 1913. The race starts at 23:30 from Navacerrada (1,858m) and runs a full circuit of the Sierra de Guadarrama's defining peaks: La Maliciosa (2,227m), La Pedriza (technical granite night section), Canto Cochino, Pradera del Yelmo, La Morcuera, Rascafría, Reventón, La Granja, the Peñalara summit (2,430m — highest point in the Community of Madrid) via the Claveles technical stone zone, Cotos, Loma del Noruego, Bola del Mundo (2,265m), and finish at Navacerrada. Aid station volunteers are RSEA Peñalara members — knowledgeable mountaineers, not race contractors — consistently praised in race reports as among the most expert in Spanish trail running. Founded 2010, the XVI GTP runs October 9–11, 2026; content is evergreen for 2027.

GTP starts at 23:30 and runs counterclockwise around the Sierra de Guadarrama. The opening hours through La Pedriza and Canto Cochino run entirely in darkness — this section is the most consistently flagged in race reports as technically demanding and a leading cause of early-race attrition. La Pedriza is a granite landscape of boulders requiring careful night navigation and footwork. After Rascafría (the main midpoint town), the route climbs from La Granja and ascends Peñalara (2,430m) via the 'Claveles' stone zone — a loose, exposed rocky approach that is the highest and most technical section of the course. Descent from Peñalara leads to Cotos, then the Loma del Noruego ridge and Bola del Mundo (2,265m) before the finish descent to Navacerrada. The 24h30 cutoff (tightened from 27h30 in earlier editions) requires consistent pacing. No GPX data is available to quantify individual climb/descent metrics.

GTP is not a first-ultra race. The organizers recommend having completed an ITRA/UTMB-listed race with 3+ points in the last three years and an ITRA/UTMB index above 400 before entering. The 23:30 start is the primary training-specificity requirement: the first 6–8 hours run in darkness through the most technically demanding sections. Train night running explicitly — headlamp navigation on rocky terrain requires different technique and pacing to daylight running. October temperatures at 2,430m on Peñalara can drop near-freezing with wind at the summit (valley typically 10–18°C); mandatory warm layers, waterproof jacket, and gloves are standard kit. The Sierra de Guadarrama weather changes rapidly in autumn. The Claveles approach is loose and exposed — comfortable experience on rocky mountain terrain above 2,000m is a prerequisite. With 5,100m D+ over 104km, the race is achievable for experienced mountain ultrarunners, but the combination of night start, cold summit, and tight cutoff creates meaningful difficulty beyond the D+/km figure.

At EUR 142 (~EUR 1.37/km), GTP is mid-range for a European 100km mountain ultra and strong value given quality and access. The 300-bib limit is genuine — registration opens annually on February 10 at 11:00 a.m. and sells out same-day; the 2026 edition had only last bibs remaining by June 2026. RSEA Peñalara's organizational quality is a consistent theme across race reports: the club founded in 1913 runs the race with genuine mountain expertise, and aid station volunteers — club mountaineers — are praised for their knowledge and care. GTP draws approximately 280–300 finishers annually with low implied DNF rates (~281 finishers from ~300 starters in 2025), suggesting a well self-selected field. The 24h30 cutoff means runners who underestimate the night section can time out. Plan entry for February 10, 2027 at 11:00 a.m. (grantrailgtp.com); first-come-first-served, no lottery.

Madrid Barajas (MAD) is the primary airport — 67 minutes to Navacerrada by car; NOT IS FAR by the DTR 180-minute threshold. By car, Navacerrada is approximately 1–1.5 hours from central Madrid depending on traffic. Public transport is viable and unusual for a mountain ultra at this level: Cercanías C8a from Madrid Atocha to Cercedilla (~1 hour) then the narrow-gauge rack railway (Ferrocarril de Cercedilla) to Puerto de Navacerrada (~30 minutes). For a 23:30 Friday race start, runners can arrive from Madrid the same day — take the train up in the afternoon, collect bibs, and start at midnight. Accommodation in Navacerrada and Cercedilla is limited; Madrid centre is a practical alternative base with easier booking. Registration opens February 10 annually at 11:00 a.m. (grantrailgtp.com); 300 bibs, first-come-first-served.