Gwent Record Office was formerly the Monmouthshire County Record Office prior to 1974. The modern county of Gwent comprises most of Monmouthshire and a small part of Breconshire. The remaining parts of Monmouthshire were transferred to the modern county of Glamorgan.
Some records for the parishes of Llanfihangel-Y-Fedw/Michaelston-y-Fedw, in old Monmouthshire may be found at the Glamorgan Record Office.
The National Library of Wales holds nearly all Bishops Transcripts and other diocesan records for Wales. The ancient dioceses covering Monmouthshire were Llandaff (most of the county) and St David's.
Some records for the parishes of Dixton, Llangiwa / Llangua and Monmouth / Trefynwy are to be found at the Hereford Record Office.
Finally, when all else fails... some parish records may still be held at the parish church - often with good reason, as perhaps a register is still in use. However please do not take too seriously any statement on individual GENUKI/MON parish pages that records are still kept by the Incumbent. Most parish registers will now be found at county Record Offices, so please do enquire there first.
If parish registers are however still with the church, a statutory fee will be levied for searches, between £15-18 per hour.
See also the ARCHON (Archives On-Line) Information service for locations of other Record Offices throughout the country.
NB: Unfortunately, the splendid Access to Archives Database covers only Archives in England at present; however a comparable source is provided by Archives Network Wales - providing a quick reference source of documents held by Record Offices, universities and other bodies throughout Wales.