Industrial Control Systems (ICS) and Supervisory Control and Data Acquisition (SCADA) systems form the backbone of critical national infrastructure, including power grids, water treatment facilities, oil and gas pipelines, and manufacturing plants. The convergence of Information Technology (IT) and Operational Technology (OT) networks, accelerated by Industry4.0 and the Industrial Internet of Things (IIoT), has dramatically expanded the attack surface of these systems. This paper presents a comprehensive review of cybersecurity frameworks specifically designed for ICS and SCADA environments, including NIST SP 800-82, IEC 62443, NERC CIP, and the MITRE ATT&CK for ICSframework. We analyze their structural components, applicability, strengths, and limitations, and propose an integrated, defense-in- depth security model that addresses the unique operational, safety, and real-time constraints inherent to industrial environments. Case studies from recent cyberattacks—including Ukraine power grid incidents and the Oldsmar water treatment plant breach—are examined to evaluate real-world framework efficacy. Findings indicate that no single framework is universally sufficient; a hybrid approach combining complementary standards yields the strongest protection posture. Future directions including AI-driven anomaly detection, zero-trust architectures, and quantum-safe cryptography in OT contexts are also discussed.