1755 = 23,381 [Source: Webster; Kyd, Scottish Historical Society 1952, iii, pp65-66]
1790s = 23,555 [Source: Thomson, 1978]
1801 = 24,445 [Source: Census]
1811 = 23,238 [Source: Census]
1821 = 26,979 [Source: Census]
1831 = 28,847 [Source: Census]
1841 = 30,451 [Source: Census]
1851 = 31,318 [Source: Census]
1861 = 32,225 [Source: Census]
1871 = 31,256 [Source: Census]
1881 = 31,884 [Source: Census]
1891 = 30,244 [Source: Census]
1901 = 27,763 [Source: Census]
1911 = 25,791 [Source: Census]
1921 = 23,933 [Source: Census]
1931 = 21,993 [Source: Census]
1951 = 21,173 [Source: Census]
1961 = 18,747 [Source: Census]
1971 = 17,077 [Source: Census]
1981 = 19,039 [Source: Census]
1991 = 19,325 [Source: Census]
2001 = 19,222 [Source: Census]
2002 = 20,000 [Source: Orkney Islands Council website.]

The Population of Orkney 1755-1961: by Robert S Barclay. Published Kirkwall 1965. 28pp.
Includes population data for individual parishes and discusses reasons for trends.

• A useful work is Scottish Population History from the Seventeenth Century to the 1930s, edited by Michael Flinn and published by Cambridge University Press in 1977.
• Another work in this field is James Kyd's Scottish Population Statistics which was published by the Scottish Academic Press in 1952 and reprinted in 1976.
• Here are some population figures for Scotland throughout the ages.

• Statistics on the population of the British Isles (archived copy).
• Histpop, the online historical population reports website, in its census section provides access to all the published population reports for Britain and Ireland from 1801 - 1937. The site has a huge amount of statistical information both at a county level and at a parish or district level. There is no personal information on the site.
• Comparative Account of the Population of Great Britain in the years 1801, 1811, 1821, and 1831. House of Commons (19 October 1831) 432pp. (Provides parish-level population counts, for England, Wales and Scotland.)