Eilean Glas first shone a light in 1789 but the present tower was constructed in 1824 and modified further in 1907.
A full description from the Northern Lighthouse Board can be found here:
Here are the keepers and their assistants from the 1851-1901 censuses.
I have included the birthplaces of children as an indication of the roving nature of the role.
Alexander Campbell, 57, Principal Light Keeper, Scalpay, b. Harris
Wife, 48, b. Inverness 4 Children (14-29) b. Harris
Chas Black, 27, Edinburgh, Assistant Light Keeper, Scalpay, b. Edinburgh
Wife, 30, b. England 3 Children (1-7) b. Aberdeenshire, Barra, and Barra.
Prudence Melvin, 56, Mother-in-Law, b. British subject, France
John Macdonald, 33, Occasional Light Keeper, Kyles Scalpay, b. Harris
Wife, 28, b. Harris 4 Children (3 weeks-7yrs) b. Harris
1852 – Revolving Lens System Installed
Ewan Campbell, 28, Light Keeper, Scalpay Island, b. Tobermory, Argyll
Wife, 30, b. Tiree, Argyll 2 Children, (?-2), b. Tiree, Argyll and Harris
David Ross, 44, Principal Light Keeper, Light House Buildings, Island of Scalpay, b. Lasswade, Midlothian
Wife, 44, b. Leith 5 Children (5-13), b. Edinburgh, Larduit, Ross-shire, and Caithness-shire
Angus Macleod, 25, Lightkeeper (Assistant), b. Durness, Sutherlandshire
Wife, 28, b. Domark(?), Dumfriess-shire, Son, 1, b. Jura, Argyll
Norman Cunningham, 28, (Amsturd St?) Keeper, Raasay,Inverness, b. Harris
Wife, 26, b. Harris 3 Children (9 months-3 yrs), b. Ardnamurchan, Argyll; Portree, Inverness
1881 – Not listed
Norman Cunningham, 42, Light Keeper (Out of Employ), Cottage, S Harris, b. Harris
Wife, 39, b. Harris 6 Children (8 months – 13 yrs), b. Ardnamurchan, Argyll; Dunrossness, Shetland; North Ronaldsay, Orkney; and Harris
Robert Murray, 44, Lighthouse Keeper, Isle of Glass Light House, b. Kirkmaiden, Wigtown-shire
Wife, 41, b. Dunnet, Caithness, Daughter, 4, b. Arbroath
Donald Douglas, 31, Assistant Lighthouse Keeper, b. Uist
Wife, 27, b. Glay(?), Argyll, Children (4, 2, 1) b. Harris
Murdo Morrison, 60, Crofter Retired Light Keeper, No 1 Kyles Scalpay, b. Harris
Wife, 26(?), b. Harris 5 Children (1-11), b.
Hugh Mackinnon, 33, Lighthouse Keeper, No 123 Lighthouse, N Harris, b. Glasgow
Kate Morrison, 32, General Servant Domestic, b. Harris
James McGuffie, 52, Driver Keeper Now Lighthouse Worker, No 124 Lighthouse, N Harris, b. Kirkmaiden, Wigtownshire
Wife, 52, b. Helmsdale, Inverness, Daughter, 26, b. Thurso, Inverness(?)
Duncan Mackay, 54, Crofter, No 125 Lighthouse, N Harris, b. Harris
Wife, 49, b. Harris, 6 Children (7-19), b. Harris
John Macsween, 62, Crofter, No 126 Lighthouse, N Harris, b. Harris
Wife, 58, b. Harris, 5 Children (9-23), b. Harris
Norman Cunningham, 63, Retired Lighthouse Keeper, Manish, b. Harris
Wife, 59, b. Harris
I find the addresses in the 1901 census particularly interesting, ‘Nos 123-126 Lighthouse’ presumably referring to the numbering system for the buildings associated with the light tower.
Norman Cunningham clearly worked in turn at Ardnamurchan, Raasay, Dunrossness and North Ronaldsay but, somewhat ironically, was unemployed on Harris in 1881 at which time no keeper of the light at Eilean Glas is to be found in these records.
There are other Harris-born lighthouse keepers spread around Scotland but I have restricted this piece to those who were resident on Harris at the time of the censuses, with the one exception of Norman Cunningham in 1871 which I considered to be an illuminating addition.