The aerodynamic forces on a cantilevered circular cylinder with an aspect ratio of 5 were experimentally investigated in a wind tunnel. The diameter of the cylinder d was 200 mm. The oncoming flow velocity ranged from 5 m/s to 45 m/s, corresponding to Reynolds number of 0.68×105 ~6.12×105, which covered subcritical, critical and transcritical regimes. It was found that, although the cantilevered cylinder is in uniform flow, its aerodynamic forces present significant differences at various spanwise positions, indicating a strong three dimensionality. Reynolds number has profound effect on the aerodynamic forces on the cantilevered cylinder. The critical Reynolds number is smaller for the cantilevered cylinder relative to that of 2D cylinder. In the critical regime, reduction in the drag coefficient (Cd) of the cantilevered cylinder is relatively smaller compared with that of 2D cylinder. In subcritical regime, Cd of the cantilevered cylinder is smaller than that of 2D cylinder. On the other hand, Cd of the former is larger in transcritical regime. The critical Reynolds number is different at various spanwise locations for the cantilevered cylinder. Transition from subcritical to critical regimes occurs earlier near the free end of the cantilevered cylinder.