Critical Infrastructure with AI Enhancement Defense is focused on protecting the types of Industrial Control Systems (ICS) or Supervisory Control and Data Acquisition (SCADA), vital to the functioning of utilities, water systems and healthcare systems as well as transportation networks. These systems are vulnerable to advanced cyberattacks due to digital transformation and integration with IT networks. These systems are at risk of highly evolved cyberattacks due to digital transformation and connections with IT networks. The paper is a discussion of growing vulnerability of SCADA and ICS and the emergence of a new role of Artificial Intelligence (AI) in improving defense strategies. The traditional approaches have miserably failed against APTs, zero-day vulnerabilities, phishing, and malware. The application of artificial intelligence (AI) in threat detection and prediction intelligence, and automated response are discussed as a potential solution to identify and prevent threats in real-time. It is revealed in the discussion that defense-in-depth, which includes segmentation, authentication, and layered monitoring with the assistance of AI insights are significant. The literature and findings presented in case studies indicate how AI can be used to transform cybersecurity through the study of evolving attack vectors. This will be more robust and effective in guarding critical infrastructure against high-level cyber threats.