You can access copies of the Diocese of Durham Bishop's transcripts for free on Familysearch:
https://www.familysearch.org/search/collection/show#uri=http://hr-search-api:8080/searchapi/search/collection/1309819The transcripts are copies of the Parish birth, marriage and burial entries that the Parish priest was supposed to send to the Bishop about once a year. The records cover the diocese of Durham which includes Cumberland, Co. Durham, Northumberland and parts of the North Riding. The Transcripts run from the 18th century to the 19th century but there are gaps in the records and some have been misplaced. Nevertheless this is a wonderful resource for anybody researching families in Co. Durham or Northumberland and who cannot get to the Records Office to view the Parish Registers.
The url above should take you to the introductory page for the records. There is an interesting description that can be accessed by clicking "Learn more" at the bottom of the QUICK FACTS box on the right of the page. To search the records you need to click "Browse through 108,812 images". This will take you to a list of the areas covered - click on an area and you will get a table of the parishes covered in that area - click on a parish to get one or more date ranges and finally click on a date range to start browsing the transcript images.
The parishes are grouped in counties which include North Durham. This area was a detatched part of County Durham and the records included on the FamilySearch site refer to the parishes of Ancroft and Cornhill, which now form part of Northumberland. Do note this North Durham does not overlap the current administrative area and constituency of North Durham.
Misplaced records that I have noticed are listed below:
Dalton le Dale in Durham is indexed as Calton le Dale.
The parishes of Durham City are listed only by date and no name as follows
Durham>Durham
1 1740-1836 Durham St Nicholas
2 1762-1841 Durham St Mary-le-Bow
3 1765-1919 Durham St Margaret includes Nevilles Cross St John
4 1773-1869 Durham St Oswald
5 1837-1838 Durham St Mary the Less
6 1813-1848 Durham Cathedral
7 1850-1919 Chapelry of St Margaret
8 1863-1893 Durham St Cuthbert
9 1878-1878 Durham St Cuthbert (burials)
There are a few index entries labelled "other". These are short runs of parish records that have become separated from the main body of the parish records. The table below lists the content of the "others".
Year range Parish No of images First LastDurham>Other
1832-1835 Chapelry of Hetton le Hole 105 15 Nov 1832 22 Dec 1835
North Durham>Other
1764-1867 Ancroft 89 29 Oct 1904 17 Nov 1812
Other>Other
1762-1864 St Helen's Aukland, Durham 1 21 Nov 1817 10 Feb 1818
1762-1876 Alwinton, Northumberland 5 13 Dec 1839 1840
1765-1849 Edmondbyers, Durham 37 13 Apr 1831 1841
1769-1851 Easington Durham 35 1 May 1774 29 Mar 1784
There is a long run of records for Wallsend, Northumberland in the Durham>Sunderland>1769 to 1842 series. Wallsend starts at image number 119 with baptisms (from 1 Jan 1813) and ends at image 695 (burials 1833). Image 697 is Sunderland burials 1770: this Sunderland series ends with a page of burials in 1820 on image 1412. As far as I can tell the early Sunderland images, 1 -118, are duplicated from 696 to 813.
JosiahS
Just a note on Dalton-le-Dale - the records are now pretty much complete to 1812 on FreeREG
FreeREG is very useful but it is only an index and does not show all the information available on the transcripts.
WolfieSmith
The Internet Archive has some free downloadable Parish Register transcriptions for Ryton, Castle Eden and Conscliffe in Co Durham.
Also Eglingham, Edlingham, Berwick upon Tweed, Alnham, Corbridge, Elsdon, Ingram and Lesbury in Northumberland.
Covers some dates not covered by the Bishops Transcripts.
Also about 50 sets of Parish Register transcriptions for Yorkshire for anybody looking further south.
New records are regularly added so worth checking back.
http://www.archive.org/search.php?query=parish%20registers%20durham