This paper provides a comprehensive survey of indoor localization techniques, technologies, and systems. It discusses various methods such as Angle of Arrival (AoA), Time of Flight (ToF), Return Time of Flight (RToF), Received Signal Strength (RSS), and Channel State Information (CSI) for indoor localization. The paper also covers different wireless technologies like WiFi, Bluetooth, Zigbee, RFID, UWB, Visible Light, and Acoustic Signals, and their applications in indoor localization. It highlights the strengths and weaknesses of these technologies and evaluates them based on factors such as energy efficiency, availability, cost, reception range, latency, scalability, and tracking accuracy. The paper also discusses the challenges of indoor localization, including multipath effects, noise, radio environment, energy efficiency, privacy, and security. It emphasizes the importance of integrating short-range and long-range IoT technologies for accurate indoor localization. The paper also discusses the potential applications of indoor localization in various sectors such as health, industry, disaster management, building management, surveillance, and the Internet of Things (IoT). It concludes that while emerging IoT technologies are not yet suitable for sub-meter accuracy, they have the potential to enhance indoor localization systems. The paper provides a detailed evaluation framework for assessing different localization systems and highlights the need for further research in this area.This paper provides a comprehensive survey of indoor localization techniques, technologies, and systems. It discusses various methods such as Angle of Arrival (AoA), Time of Flight (ToF), Return Time of Flight (RToF), Received Signal Strength (RSS), and Channel State Information (CSI) for indoor localization. The paper also covers different wireless technologies like WiFi, Bluetooth, Zigbee, RFID, UWB, Visible Light, and Acoustic Signals, and their applications in indoor localization. It highlights the strengths and weaknesses of these technologies and evaluates them based on factors such as energy efficiency, availability, cost, reception range, latency, scalability, and tracking accuracy. The paper also discusses the challenges of indoor localization, including multipath effects, noise, radio environment, energy efficiency, privacy, and security. It emphasizes the importance of integrating short-range and long-range IoT technologies for accurate indoor localization. The paper also discusses the potential applications of indoor localization in various sectors such as health, industry, disaster management, building management, surveillance, and the Internet of Things (IoT). It concludes that while emerging IoT technologies are not yet suitable for sub-meter accuracy, they have the potential to enhance indoor localization systems. The paper provides a detailed evaluation framework for assessing different localization systems and highlights the need for further research in this area.