Structures can experience localized damages for various reasons, and if the location of these damages remains unknown, they can be exacerbated due to natural disasters such as earthquakes or artificial factors like improper excavations, leading to their destruction. Therefore, monitoring the health of structures and their components is considered one of the most important research topics in civil engineering, mechanical, and aerospace disciplines. Numerous research studies have been published so far in the field of structural health monitoring. Nowadays, with the use of structural health monitoring methods, it is possible to accurately identify structural damages in the early stages and prevent financial and life-threatening damages from occurring. Structural health monitoring is essential to ensure the safe performance of a structure throughout its operational lifespan. Due to the typically uncertain location and severity of damage in structures, significant efforts have been made to achieve an accurate, reliable, and cost-effective method for damage detection. The detection of damage in structures, especially in recent years, has received significant attention. A comprehensive review of published research studies has been conducted in this chapter and an overall description was provided of various methods and compared them in terms of accuracy and correctness.