1850 Counties of Massachusetts
| in area | Courts held at | Pop in 1850 | ||
| Barnstable Co, MA | in extreme eastern part, whole of Cape Cod & Elizabeth Island. Atlantic on south & East, Cape Cod bay on north & Buzzard bay on west | 325 sq miles | Barnstable | 35,276 |
| Berkshire Co, MA | on western side | 1,400 sq miles | Lenox | 49,591 |
| Bristol Co, MA | southeast part, on Buzzard's bay & Rhode Island line | 600 sq miles | New Bedford & Taunton | 74,577 |