Trail running has grown rapidly over the past decade, yet gender disparities in participation and performance remain poorly documented at scale. This data paper presents TRAILGENDER, an open-access, multi-source database harmonising race-level and athlete-level records from two data flows combining three open-access datasets. The database covers 15,848 race editions across 95 countries from 2010 to 2021, totalling 1,081,544 individual performances standardised across nine distance brackets (10K to EXTREME). TRAILGENDER v4 comprises 12 structured worksheets with 94 documented variables, including standardised distance brackets, gender performance gaps, temporal series, country-level aggregates, and a novel composite metric—the Gender Selection Index (ISG). All data underwent systematic quality control (two rejection codes, 876 rejected records preserved for traceability) and technical validation through four sensitivity analyses and cross-source triangulation. The database is deposited on Nakala (Huma-Num, CNRS) under a CC-BY 4.0 licence (DOI: 10.34847/nkl.cbbc2i86) and is designed for reproducible research in sport sociology, gender studies, exercise science, and data science.

Trail running has grown rapidly over the past decade, yet gender disparities in participation and performance remain poorly documented at scale. This data paper presents TRAILGENDER, an open-access, multi-source database harmonising race-level and athlete-level records from two data flows combining three open-access datasets. The database covers 15,848 race editions across 95 countries from 2010 to 2021, totalling 1,081,544 individual performances standardised across nine distance brackets (10K to EXTREME). TRAILGENDER v4 comprises 12 structured worksheets with 94 documented variables, including standardised distance brackets, gender performance gaps, temporal series, country-level aggregates, and a novel composite metric—the Gender Selection Index (ISG). All data underwent systematic quality control (two rejection codes, 876 rejected records preserved for traceability) and technical validation through four sensitivity analyses and cross-source triangulation. The database is deposited on Nakala (Huma-Num, CNRS) under a CC-BY 4.0 licence (DOI: 10.34847/nkl.cbbc2i86) and is designed for reproducible research in sport sociology, gender studies, exercise science, and data science.