This study investigates the influence of active tectonics on the drainage patterns and geomorphic characteristics of the Rit Anticline, located within the Simply Folded Belt of the Zagros fold-and-thrust belt. Morphometric analysis was conducted for 93 drainage basins using six basin-scale indices (AF, HI, Bs, CI, Smd, and SL) and drainage-network parameters (Dd, Dd1, Df, N1/N, and Sd).One-way ANOVA and pairwise Welch t-tests identified significant among-sector variation in four parameters: HI (F = 5.946, p = 0.003), CI (F = 3.178, p = 0.046), Smd (F = 3.125, p = 0.048), and SL (F = 3.021, p = 0.036), while AF and Bs showed no significant variation, reflecting the structural coherence of the anticline as a continuous fold. The western sector is morphometrically the most distinct: significantly higher CI (1.54 vs. 1.18, p = 0.032), HI (0.500 vs. 0.488, p = 0.009), and lower SL (317.5 vs. 441.5, p = 0.028) relative to the central sector, and higher Smd (1.19 vs. 1.1, p = 0.007) relative to the eastern sector, consistent with more advanced lateral fold propagation in this zone. No significant differentiation between the central and eastern sectors supports the interpretation that eastward propagation remains at an earlier stage. A strong negative correlation between Bs and CI (r = −0.411, p < 0.01) suggests geometric compensation between basin elongation and crescent-shaped deformation. Overall, the Rit Anticline is characterized by asymmetric bilateral lateral propagation, more advanced to the west, governed by fault-related folding, transverse–shear faulting, and spatially variable lithologic resistance.