Post Offices List in New Castle City, Delaware:
| Centerpoint Post Office | 105 Johnson Way, New Castle, DE 19720 |
| New Castle Post Office | 501 Delaware St, New Castle, DE 19720 |
| Manor Post Office | 100 Mcmullen Ave, New Castle, DE 19720 |
| Wilmington Box Post Office | 147 Quigley Blvd, New Castle, DE 19720 |