Thanks to many years of work by members of the Chiefly kin in Scotland during the 20th century there is a fairly large volume of work which has been published and which should be reviewed first. These mostly involve the publication of transcriptions of original documents.
Genealogist Herbert Campbell of the Duntroon family published extensive Notes on Campbell families of the Chiefly Kin and these are to be found in typescript at the Lyon Office next to the Register House in Edinburgh. The CCS(NA) Library has photo-copies.
Campbell of Barcaldine employed a genealogist by the name of Paton to transcribe all Campbells noted in the Sheriff Court books of Inveraray, the Register of Sasines for Argyll (title deed lists) and the Hornings (notices for arrest) and other public records. Paton also transcribed some records for Perth and Ayr and entries from early newspapers in Edinburgh and London. Unfortunately only those entries related directly to Campbells were transcribed. Associated names were only transcribed where they interacted with Campbells. The several volumes which were published by Barcaldine at some considerable sacrifice to himself, are the largest body of transcriptions of Campbell related material and copies are in the CCS (NA) Library.
The bulk of Scottish records which survive remain in the Scottish Records Office in Edinburgh, often called the SRO. These, of course, are for the whole country and the entries of Campbell interest are not separated from the others. The largest body of Campbell-related papers in the SRO are the Breadalbane papers and cataloguing of these is now complete. These of course relate mostly to Perthshire but also to Glenorchy, Kilchurn, Ardmaddy and Luing in Argyll.
There are a number of Campbell papers in the National Library of Scotland in Edinburgh and a copy of the catalogue of these will, one hopes, be compiled. At present the Campbell related papers must be found in the general catalogs.
Some of the main sources to be found in the SRO are as follows:
These are generally known as the OPR and precede the official registers which were only started by law in 1855. The pre-1855 registers were kept intermittently by some parish ministers and these are the OPR. They are a source for some births, (mostly baptisms) marriages and occasionally deaths and in some places are useful as they give the names of the farms or communities from which the people came. However they were not kept regularly and not all have survived. Those which started in the 17th century require some expertise to read. The oldest for Argyll are Inveraray from 1653 and Campbeltown Lowland Church, 1659. First check Key to the Parochial Registers of Scotland, Brigham Young University Press, 1970.
After 1855 the registers give birth, marriage and death dates. Mac and Mc are used indiscriminately in early entries so check for both where looking for such names. There is a Birth Index, a Marriage Index and a Death Index.
The Census was first taken in 1841 and thereafter every ten years, the information of the first being somewhat sketchy, however the later schedules give much information.
The minutes of the meetings of the Kirk Sessions in each parish contain a great variety of information from additional information on regular and irregular marriages to pew rents, headstones, the poor, orphans and widows. Some of these are in the SRO and some still in the parishes.
The Minutes of the Synod of Argyll, 1639-1651, were transcribed by Duncan McTavish and published by the Scottish History Society in two volumes. These records are of interest where "heritors" or landowners responsibilities to the kirk are concerned.
Sasine in Scotland meant the act of transfer of land ownership by grant, inheritance or sale from one party to another and was long completed on the ground by the actual passing of a symbolic handful of earth. The Sasine Registers began to be kept in some areas in the 16th century. The language used is formal and full. Out of six pages you may only find two core paragraphs which carry the essence of the transaction involved. This means that it may be simpler to have a researcher transcribe what you want than to ask for a photo-copy.
People who had failed to pay a debt or to fulfill the requirement of a court of law might be "Put to the Horn" or given notice of arrest. The practice was mainly recorded in the 16th and 17th centuries.
These are recordings of court proceedings and often give the names of witnesses and jury members besides those charged or accusing.
The records of trials held in Argyll between 1664 and 1707 were transcribed by John Cameron and published by the Stair Society in 1949. They contain information similar to the Sheriff Court Books.
The Hearth Tax was like a Poll Tax which was instituted by King William of Glencoe fame as a means to finance his European wars. They were only listed in one year in the late 17th century but give a fair population count for many communities and also indicate which families were more prosperous, having more than one hearth. The listing for Jura is very cursory but listings are full for most other parts of Argyll.
There was a list made of those in Argyll who came out as a militia for the 9th Earl of Argyll in 1685 and so were termed rebel. This was published as The Commons of Argyll by Duncan McTavish. However the official government militia dates more from the Jacobite rising and the later Napoleonic wars. Lists may exist for some of these periods. Military records for Scottish regiments which are not at the museums of those regiments in Scotland may be found at the Kew department of the PRO or Public Records Office in London.
For Society members in the United States (or Canada) who have traced their ancestry to Scotland, the CCS(NA) Genealogist and Librarian may be able to offer some assistance from secondary sources (i.e., published material) in the CCS(NA) Library. The fee for a search of the CCS(NA) archives is $10 ($5 for members).
If a Campbell family can be traced to an actual location in Argyll (other than just "Inveraray" which was often added by early family members since they heard Campbell chiefs came from there), the chief executive of Clan Campbell at Inveraray Castle may be able to offer some suggestions. Donations for archival services at Inveraray should be agreed with the chief executive.
These are by no means all the sources to be investigated but will offer you the best known and easiest of access for a start.
The LDS or Mormon archives have microfilmed many of the documents in the SRO, and you may find that you can save funds by visiting your local Stake House (LDS church) to ask about availability before sending funds overseas for research. The value of any microfilm depends upon the care with which it was made. Equally any transcriptions depend upon the reliability of the transcriber. For ultimate confirmation you may have to obtain a photo-copy of the original document.
For those who have traced their ancestry to Ireland: If your family were Protestants they likely lived in Ulster for which the records are in Belfast. If they were Catholic they may have lived in what is now the Republic of Ireland in which cases the records in Dublin were burnt in the struggle for independence, however there are copies in Belfast. Be aware that, due to the Provo and IRA terrorists, the Belfast Records Office and Library are under strict security and you may well do best to ask for the name of a local researcher who has clearance.