Newcastle Hundred faces the Bristol Channel between Ogmore Hundred and Neath Hundred. It stretches inland to the detached part of Ogmore Hundred.
A Vision of Britain through Time provides the following description of Newcastle Hundred from John Marius Wilson's Imperial Gazetteer of England and Wales of 1870-72:
- "NEWCASTLE HUNDRED contains twelve parishes. Acres: 71,276. Pop.in 1851: 20,157; in 1861: 24,575. Houses: 4,771.
GENUKI provides a map from 'Historic Parishes of England and Wales - Boundaries before 1850' to which the boundaries of the hundreds have been superimposed. Dates are those for earliest parish registers. (Full source notes for the original map on the GENUKI page.)
List of Parishes
Parish | Description | Notes
| Betws Tir Iarll | parish (ancient), civil parish |
| Coety Higher | hamlet, parish (ancient), civil parish |
| Coety Lower | hamlet, parish (ancient), civil parish |
| Coychurch | parish (ancient), civil parish |
| Coety | parish (ancient), civil parish |
| Kenfig | parish (ancient), civil parish |
| Laleston | parish (ancient), civil parish |
| Llangynwyd | parish (ancient), civil parish |
| Margam | parish (ancient), civil parish |
| Newcastle | parish (ancient), civil parish |
| Newcastle Higher | hamlet, parish (ancient), civil parish |
| Newton Nottage | parish (ancient), civil parish |
| Peterston super Montem | parish (ancient), civil parish |
| Pyle | parish (ancient), civil parish |
| St. Brides Minor | parish (ancient), civil parish |
| Tythegston | township, parish (ancient), civil parish |
| Sger | parish (ancient), civil parish |
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