The origin of the name St Kilda is a matter of conjecture.  Various theories have been proposed for the word Kilda's origin, which dates from the late 16th century (no saint is known by the name).   Haswell-Smith (2004) notes that the full name St Kilda first appears on a Dutch map dated 1666, and that it may have been derived from Norse sunt kelda ("sweet wellwater") or from a mistaken Dutch assumption that the spring Tobar Childa was dedicated to a saint.  The islands' human heritage includes numerous unique architectural features from the historic and prehistoric periods, although the earliest written records of island life date from the Late Middle Ages.  The medieval village on Hirta was rebuilt in the 19th century, but the influences of religious zeal, illnesses brought by increased external contacts through tourism, and the First World War all contributed to the island's evacuation in 1930.

St Kilda may have been permanently inhabited for at least two millennia, the population probably never exceeding 180 (and certainly no more than 100 after 1851).  The entire remaining population was evacuated from Hirta (the only inhabited island) in 1930.  Currently, the only year-round residents are military personnel but a variety of conservation workers, volunteers and scientists spend time there in the summer months.

The entire archipelago is owned by the National Trust for Scotland.  It became one of Scotland's five World Heritage Sites in 1986 and is one of the few in the world to hold joint status for its natural and cultural qualities.

Two different early sheep types have survived on these remote islands, the Soay, a Neolithic type, and the Boreray, an Iron Age type.  The islands are a breeding ground for many important seabird species.  One of the world's largest colony of Northern Gannets, totalling 30,000 pairs, amount to 24 percent of the global population.  There are 49,000 breeding pairs of Leach's Petrels, up to 90 percent of the European population; 136,000 pairs of Atlantic Puffins, about 30 percent of the UK total breeding population, and 67,000 Northern Fulmar pairs, about 13 percent of the UK total.  Dùn is home to the largest colony of Fulmars in Britain.  The last Great Auk (Pinguinus impennis) seen in Britain was killed on Stac an Armin in July 1840.  The St Kilda Wren and St Kilda Field Mouse are endemic subspecies.

Several companies offer day trips to St. Kilda - I went with Kilda Cruises in June 2013.

The eagle eyed among you may notice that some of my photographs are marked '2012'.  This was a mistake but I couldn't be bothered to do them all again.