How far did the fertile crescent stretch from north to south?

In the North, the northernmost part of the Fettle Crescent was in today's Turkey, around today's border of Turkey and Iran.

In the South, it was the South of the Nile, the River, on one side, and the northernmost part of the Persian Gulf on the other side. 

In total, this is about 5000 km from North to South.

The answer is price.