Hexagonal boron nitride (h‐BN) has emerged as a strong candidate for two‐dimensional (2D) material owing to its exciting optoelectrical properties combined with mechanical robustness, thermal stability, and chemical inertness. Super‐thin h‐BN layers have gained significant attention from the scientific community for many applications, including nanoelectronics, photonics, biomedical, anti‐corrosion, and catalysis, among others. This review provides a systematic elaboration of the structural, electrical, mechanical, optical, and thermal properties of h‐BN followed by a comprehensive account of state‐of‐the‐art synthesis strategies for 2D h‐BN, including chemical exfoliation, chemical, and physical vapor deposition, and other methods that have been successfully developed in recent years. It further elaborates a wide variety of processing routes developed for doping, substitution, functionalization, and combination with other materials to form heterostructures. Based on the extraordinary properties and thermal‐mechanical‐chemical stability of 2D h‐BN, various potential applications of these structures are described. h‐BN is one of the most promising inorganic materials of this century, with possible applications ranging from aerospace to medicine. It has emerged as an exotic 2D material in the post‐graphene era, owing to its exciting optoelectrical properties combined with mechanical robustness, thermal stability, and chemical inertness. An encyclopedic view of the structure, properties, synthesis, and applications of h‐BN is provided.