The kingdom of Saudi Arabia (KSA) is the fifth largest country in Asia and the largest in the Middle East. Such vast area resulted in having different geographical, geological, and climatic conditions throughout the kingdom which significantly affected the structural and architectural characteristics of the Saudi historical vernacular buildings and accommodation facilities. From structural perspective, the available local construction row materials, the climatic conditions and the geographical location associated with economic activities were the main driving forces behind varying the structural characteristics of heritage residential houses in Saudi cities. This study examines the impact of geological, geographical, and climatic diversity on the construction techniques of historical buildings in the kingdom through investigating the structural characteristics of these buildings in three regions of the kingdom. Also, it provides information on the mechanical characteristics of these construction materials as determined from testing large number of samples. The considered regions are old Jeddah city (Al Balad) located along the coast of red sea in west of the kingdom, the historical Al-Dirayah district located close to Riyadh city in the central region of the kingdom and Abha city in southern region of the kingdom.