In this study, a Hastelloy C276 thin-wall structure was fabricated by wire arc additive manufacturing (WAAM). The microstructure and mechanical properties of the as-deposited structure were evaluated in detail using specimens extracted from different orientations and locations along the deposition direction. The results show that the primary dendrite arm spacing, dislocation density, and second-phase precipitates change along the deposition direction of the material, and they are responsible for the occurrence of anisotropy and heterogeneity in the observed mechanical properties. However, the well-distributed hardness values generated in the as-deposited sample are considered to be due to the uniform directional dendrites. This study enables a better understanding of the WAAM processing-microstructure-properties relationship for the nickel-based alloy, providing useful information for process optimization and improvement in the resultant mechanical properties.