26 zips
| Zip Code | City | Population ↓ |
|---|---|---|
| 06457 | Middletown | 46,690 |
| 06416 | Cromwell | 14,301 |
| 06413 | Clinton | 13,317 |
| 06424 | East Hampton | 12,401 |
| 06475 | Old Saybrook | 10,515 |
| 06371 | Old Lyme | 9,855 |
| 06480 | Portland | 9,421 |
| 06422 | Durham | 7,182 |
| 06498 | Westbrook | 6,832 |
| 06419 | Killingworth | 6,219 |
| 06441 | Higganum | 5,323 |
| 06423 | East Haddam | 5,163 |
| 06417 | Deep River | 4,432 |
| 06412 | Chester | 3,786 |
| 06426 | Essex | 3,285 |
| 06469 | Moodus | 3,125 |
| 06438 | Haddam | 3,012 |
| 06442 | Ivoryton | 2,623 |
| 06455 | Middlefield | 2,592 |
| 06481 | Rockfall | 1,644 |
| 06459 | Middletown | 956 |
| 06409 | Centerbrook | 858 |
| 06414 | Cobalt | 407 |
| 06456 | Middle Haddam | 253 |
| 06376 | South Lyme | 87 |
| 06439 | Hadlyme | 58 |
The data shown reflect ZCTAs from the US Census. As of 2024, there are 26 ZCTAs in Lower CT River Valley Planning Region, Connecticut (US Census).