A Streetmap.co.uk map of the area shows the village, which is divided into a northern group of dwellings, Lower Sanna, and a more dispersed southern group, Upper Sanna. The extent of the beaches is evident, as is the miles of coastline and open moorland which also make Sanna a wonderful centre for those who enjoy walking. But, other than a fort to the north of Sanna, the present 1:25,000 OS map shows little evidence of the settlement's long history. 
Humans have been living at Sanna for thousands of years. The machair, the shell-sand area that lies between the village and the sea, was home to groups of Bronze Age people (2,800 - 1,800 BC) who camped near the beach and enjoyed shellfish suppers. A paper by T C Lethbridge published in 1927 by the Royal Anthropological Institute of Great Britain and Ireland describes two layers of human activity exposed in the dunes, each of them continuous for some hundred yards. In the upper layer he found a bronze broach and a pin which he dated to the 8th or 9th century. He found two areas if interest in the lower. One he describes as a midden, a rubbish dump, containing pieces of Bronze Age pottery made by Beaker people, flint knives, axe heads, and a barbed arrow head. Not far away, he found another midden, but this also showed signs that it might have been a cremation site, consisting of burn bones surrounded by pebbles the size of oranges. Some of the artifacts are in the Museum of Archaeology and Anthropology at the University of Cambridge (link here) and, for those of you who have access to JSTORE, Lethbridge's paper is here. Further finds have been made by others - for example, arrow heads, borers and and scrapers were found by R Crerar, and reported in a paper in 1961.
Lethbridge's broach and pin are good evidence of occupation in the first millennium AD, and the Vikings must also have known Sanna and used its beaches, though I don't know of any evidence that they settled there other than the name itself. This is said to derive from the Norse words sandr, sand, and ey, an island. 
When William Roy made his military map in 1747 (above), the village of 'Sand' is clearly marked. For its time, Roy's map was an incredible achievement, but it is far from accurate. For example, the number of red marks does not necessarily indicate the number of buildings. The Sanna Burn is shown as reaching the sea near the now-ruined village of Plocaig. Either Roy was mistaken or, as Bob Jones from Suffolk has suggested, this might have been the original course of the Sanna Burn, which was later diverted, either by man or naturally. Roy's positioning of the Sanna houses suggest they were on a site which today would have been beside the burn, with the worked land in the flat area to the south of them. 
Roy's record of the amount of worked land would suggest several inhabitants in 1747, but the Kirk Session of Ardnamurchan Parish in 1779 record only one inhabitant at Sanna, Archibald MacArthur, a shepherd. (SC)
The first Scottish census in 1841 lists 18 families in Achosnich. It may be that there were no permanent residents in Sanna, the land being tended by farmers from either Achosnich or Achnaha. However, in 1853 sixteen tenants from the three Swordle settlements approximately fourteen miles away along the north coast were cleared from their homes by the then landlord of Ardnamurchan, James Miles Riddle, and assigned an acre each of Sanna land. (SC) and 
 and (SC)
The 1881 census shows this considerable shift in population. Included in this census was the population of Plocaig a small now derelict row of houses a quarter of a mile east, giving some 22 houses and 85 people in total. Many of the heads of households are listed as women and there is a distinct lack of work age men. (SC)
The revised OS 6" map, surveyed in 1897, shows little change from 1872 except that the lochan has been drained, and there are a few more buildings both north of the Sanna Burn and at the south end of the settlement. The connection is still south to Achosnich - but the tracks are marked as 'footpaths'. 
Neither of these early OS maps show the four ruined stone buildings to be found some 300m to the north of the bridge over the Sanna Burn, described in Diary posts here and here, so they remain a mystery. links to follow
Some time in the 1890s the small church hall was built. It had no denomination and was used alternately by the Church of Scotland and the Free Church, indicating that the Sanna people attending worship must have been of split between the denominations. (SC)
By the early 20th century, the people of Sanna were campaigning for a road to connect their village to the road which had, by now, reached Achnaha. MEM Donaldson, who later built Sanna Bheag, the large house at the southern end of the settlement, describes in her Further Wanderings - Mainly in Argyll (1926) the battle the crofters had to get their road built. With many of the men away, 'mostly in the merchant service', all goods for the village, such as fuel, building materials and other provisions, had to be carried in from Achnaha on the women's backs. Worse, she describes the hardships of having to carry a coffin along the track to Achnaha, as all burials took place in Kilchoan. By 1925 the road had been built, but the story suggests that, a couple of decades previously, Sanna was already connected more to Achnaha than Achosnich.
MEM Donaldson goes on to describe the village as having twenty houses built of stone with reed thatched roofs, of which one 'is over a hundred years old'. The older cottages were of the 'but and ben' type, and some still had floors of beaten earth. However, all by now had chimneys, made of cones of thatch, but their water came from the nearest burn. The crofters paid an average of £1 12s and 6d a year to the landlord for their land, but this also gave them a share of the common grazing on which they could graze 'two cows and their followers'. The grazings was overseen by a committee of three crofters, elected every three years. She noted that, 'There are only cows at Sanna, and horses and sheep are not allowed'. The crofters also kept chickens, grew potatoes and 'corn', and caught fish.
Related blog posts:
A Sanna Settlement Discovered -1
A Sanna Settlement Discovered - 2
 An interactive Streetmap is here
 ElectricScotland, link here.
 Ardnamurchan Place Names - Angus Henderson, extract from the 'Celtic Review' of 1915
 William Roy's Military Map of Scotland, 1747-55, by kind permission of the British Library Board. View the map on the National Library of Scotland's website here.
 William Bald's 'Plan of Ardnamurchan and Sunart, Argyll', 1806, by kind permission of the National Records of Scotland. View the map here.
 OS 6" map, surveyed in 1872, by kind permission of the National Library of Scotland. View the full map here.
 OS 6" map, surveyed in 1897, by kind permission of the National Library of Scotland. View the full map here.
(SC) Information from Sue Cheadle.
Many thanks to Sue Cheadle and Judy Crerar for their help.
This 'Page' of the Kilchoan Diary can be updated. I am very keen to add any information that readers are able to give me either through Comments or by email - I can be contacted at email@example.com