Where land meets the sea, conditions change abruptly. The coast is the zone of interaction between terrestrial and marine environments. It includes beaches, cliffs, estuaries, dunes, and the shallow waters just offshore.

Waves, tides, and currents constantly reshape the shoreline. Rivers deliver sediment that builds deltas and barrier islands. Human settlements have long clustered along coasts for fishing, trade, and transport, making these areas both valuable and vulnerable.

Sea-level rise and increased storm intensity now threaten many coastal communities. Management strategies range from engineered seawalls to restored wetlands that absorb wave energy. The coast remains one of the most dynamic and contested landscapes on Earth.

• Land area bordering ocean or sea
• Shaped by waves, tides, and sediment
• Supports dense human settlement
• Highly vulnerable to sea-level rise