Canna is the westernmost of the Small Isles archipelago, in the Scottish Inner Hebrides. It is linked to the neighbouring island of Sanday by a road and sandbanks at low tide. The island is 4.3 miles (6.9 km) long and 1 mile (1.6 km) wide. The isolated skerries of Hyskeir and Humla lie 6.2 miles (10.0 km) south west of the island.
The islands were left to the National Trust for Scotland (NTS) by their previous owner, the Gaelic folklorist and scholar John Lorne Campbell in 1981, and are run as a farm and conservation area. Canna House, one of two big houses on the island (the other being Tighard), contains John Campbell's important archives of Gaelic materials that were donated with the islands to the nation. Since then the NTS has engaged in new initiatives to attract new residents and visitors to the island.
There are some 20 buildings on Canna and Sanday, including three churches, one of which has been deconsecrated (see below). There is also a post office which was converted from a garden shed. The Canna tea room, which closed in 2008, reopened in 2010 as the Gille Brighde Cafe and Restaurant. A new resident manager for the island was also appointed in the same year. The island is isolated and the inhabitants must buy their provisions from the mainland, but it has a telephone link, a red telephone box and broadband internet access, although there is no mobile phone coverage. Electricity is provided by a diesel generator, at mainland voltage and frequency, and there is a private water supply. In 2010 a proposal to establish a fish farm off Canna was defeated in a residents' ballot, even though it would have created a number of new jobs.
The island has a very low crime rate, but a mainland-based policeman visits the island twice a year, mainly to inspect gun licences. A doctor based on the neighbouring island of Skye is available for house calls once a month. The roads on Canna are not metalled and are privately owned; local vehicles therefore do not require road tax. The previous footbridge to Sanday was destroyed by storms during 2005, and has recently been replaced by a road bridge. This allows vehicular access at all tide levels for the first time, although the road on Sanday is still covered by high tides.
Canna is renowned for its wildlife, including sea eagles, golden eagles and puffins. Recently, peregrine falcons and merlins have been sighted also. The island is also inhabited by a number of rare butterfly species. In the nearby waters one can spot dolphins and smaller whales.
Canna is noted for its tiers of basalt pillars that rise over the eastern half of the island and the sea cliffs that dominate its northern shore. The highest point on the island is Càrn a' Ghaill (Gaelic for rocky hill of the storm) at 689 feet (210 m). Another point of interest is Compass Hill. Its peak is at 456 feet (139 m) and sits on the eastern edge of the island. It is made of a volcanic rock called tuff, and it has such a high iron content that the compass of nearby ships are distorted, pointing to the hill rather than north.