| Rank | County | GCP |
| 1. | Nairobi | $27.80 billion |
| 2. | Nakuru | $10.33 billion |
| 3. | Kiambu | $8.43 billion |
| 4. | Mombasa | $6.63 billion |
| 5. | Nyandarua | $4.90 billion |
| 6. | Machakos | $4.65 billion |
| 7. | Meru | $4.59 billion |
| 8. | Kisumu | $3.88 billion |
| 9. | Bungoma | $3.66 billion |
| 10. | Kakamega | $3.65 billion |
