The National Archive of Scotland (NAS) is the main repository for sources of Scotland's history as a separate kingdom, her role within the British Isles, and her links with other countries over the centuries. The NAS holds records spanning the 12th to the 21st centuries, touching on virtually every aspect of Scottish life, including the public and legal records of Scotland, and many local and private archives. It also advises Scottish government departments, institutions, businesses and private individuals on the care of their records.

Records can be consulted in two buildings: General Register House and West Register House. Housed in the former, the Historical Search Room is generally recommended for initial research into family or local history. Its holdings include church records, the papers of landed and noble families, business and property records, within the following main categories:

- Records of the pre-1707 Scottish Government and Parliament; Privy Council; Treasurer's Accounts; Registers of the Great and Privy Seal.

- Records of the parish kirk sessions of the established Church of Scotland, the Free Church, and the various dissenting ('seceding') congregations; copies of the records of baptisms, marriages and burials for Roman Catholics before 1855.

- Legal Registers: Registers of Deeds and Sasines; Services of Heirs.

- Early Court of Session records; Justiciary Court records (pre 1800); some sheriff court and commissary court records.

- Local records: Burgh records; valuation rolls.

- Private records: family, legal and estate papers; records of businesses, societies and institutions.

The West Search Room holds material relevant to research into legal cases, government policy after 1886, railways, mining, engineering, geography and architecture, including information on the lives of workers in these fields. Its main holdings include:

- Modern government files: records of the Scottish Office and Scottish Executive.

- Court records: Court of Session; Justiciary Court (post 1800); some sheriff court records.

- Records of the former nationalised industries: coal, rail, gas, electricity and steel.

The West Search Room also houses almost all maps and plans held within the NAS, which can be searched via electronic and paper catalogues, as well as a card index.