Cairo: The Capital at the Nile's Mediterranean Doorstep (31°E)

The national capital located near the mouth of a river emptying into the Mediterranean Sea at approximately 31°E longitude is Cairo, Egypt.

The Geography

• River: Nile River (world's longest, ~6,650 km)
• Delta: Nile Delta fans out north of Cairo; the river splits into two main branches (Damietta/Rashid) reaching the Mediterranean.
• Coordinates: Cairo ~30.0°N, 31.2°E. The Nile's mouth (Rosetta/Damietta) ~31.4°E, 31.5°N.
• Proximity: Cairo sits at the apex of the delta, ~100 km (60 mi) south of the Mediterranean coast.

Why Cairo Fits the Clue

1. Capital: Yes, Egypt's capital and largest city (~22M metro).
2. River Mouth: Nile empties into Mediterranean.
3. Longitude ~31°E: Cairo (31.2°E), Nile mouths (31.4–31.5°E) — matches precisely.
4. Historical/Modern Role: Gateway between Nile Valley and Mediterranean world for 5,000+ years.

Other Capitals Near Mediterranean River Mouths (for comparison)

Only Cairo matches all criteria: national capital, major river (Nile) emptying into Mediterranean, longitude ~31°E.