Professional wildland firefighters are exposed to substantial physical, thermal, respiratory, and psychosocial demands. This cross-sectional study examined whether cardiometabolic and work-related health indicators differed among the five provinces of Castilla-La Mancha after accounting for age and sex. The analytical sample comprised 757 salaried GEACAM wildland firefighters (663 men and 94 women). Outcomes were visceral fat level, device-derived metabolic age, metabolic age gap, the Work Ability Index (WAI), the 14-item Perceived Stress Scale (PSS-14), self-rated health, and anxiety problems. Province effects were tested using heteroscedasticity-robust linear models or logistic regression, with age and sex as covariates. Adjusted pairwise provincial contrasts were corrected using Holm’s method. Province was associated with visceral fat level (F(4, 687) = 3.21, p = 0.013, partial R² = 0.021) and PSS-14 score (F(4, 685) = 4.64, p = 0.001, partial R² = 0.029). No adjusted provincial association was found for metabolic age, metabolic age gap, WAI, self-rated health, or anxiety problems. After Holm correction, PSS-14 scores were lower in Albacete than in Guadalajara (adjusted difference = −3.17, 95% CI −5.18 to −1.16; pHolm = 0.018) and Toledo (−3.54, 95% CI −5.36 to −1.72; pHolm = 0.001). Although the global province effect for visceral fat was significant, no individual pairwise contrast remained significant after Holm correction. Provincial heterogeneity was therefore modest and concentrated in perceived stress and, less conclusively, visceral fat. These findings support age- and sex-adjusted surveillance while precluding causal explanations based on terrain, fire exposure, workload, or recovery, none of which were measured.