A coastal plain is flat, low-lying land adjacent to a sea coast. Some of the largest coastal plains are in Alaska and the southeastern United States. The Gulf Coastal Plain of North America extends northwards from the Gulf of Mexico along the Lower Mississippi River to the Ohio River, which is a distance of about 981 miles (1,579 km).
The Coastal Plains of India lie on either side of the Peninsula Plateau, along the western and eastern coasts of India. They extend for about 6,150 km from the Rann of Kutch in the west to West Bengal in the east. They are broadly divided into the Western Coastal Plains and the Eastern Coastal Plains. The two coastal plains meet at Kanyakumari, the southern most tip of the Indian mainland.
- "coastal plain". 1996-2015 National Geographic Society.