Buiston Loch (NS 416 433) locally pronounced 'Biston', also known as Buston, was situated in the mid-Ayrshire clayland at an altitude of 90m OD. It is visible as an often flooded surface depression in pastureland situated in a a low lying area close to the A735 road between the the farms of Lochside, Buistonend and Mid-Buiston. The loch was natural, sitting in a hollow created by glaciation. The loch waters drained via the Garrier Burn that joins the Bracken and Lochridge Burns before joining the Irvine. Thye loch is well documented through the presence of a crannog or lake-dwelling, first excavated 1880-1.

Late 16th century records, show a substantial triangular-shaped loch , however by the mid-eighteenth century the loch appears to have been drained. The Garrier Burn draining the site is marked on a map of 1828, however it has been canalised or 'ditched' and field drains added by the mid 19th century, as part of an improved drainage system. Around 1830 the loch was described as being a mossy bog in the summer and a sheet of water throughout the winter;  by 1880 it was a cultivated meadow.

Buiston was a post-glacial loch situated on the lands of Mid-Buiston, for many years the property of the Earls of Eglinton and the crannog was at first believed to be a structure built by the Earl's of Eglinton to house a shelter for shooting waterfowl^. Evidence of the original shoreline persists on the northern side of the loch basin.

The roughly circular crannog, known as the 'Swan Knowe', lay around 70m from the northern shore and was first identified in 1880 from 'worked' timbers located within the drainage 'gote' or ditch on the site by a teacher from Kilmaurs, Duncan McNaught. The site was first excavated in 1880 - 1881. In 1989-90 the site was re-excavated. Finds included a rare fourth century hanging bowl, dugout canoes, and numerous wood, stone, bone and metal items.

The crannog had four periods of occupation, dating from AD1 to AD 525. Three log boats or canoes seem to have been found, the one in 1989-90 was left on site, another was lost in a fire at the Dick Institute in 1909 and the third may survive in the Hunterian Museum in the form of an unprovenanced specimen.

Much timber had been taken away prior to the crannog's identification. It was constructed from successive layers of turves, stones, intermingled within a network of branches and tree trunks. No gangway was found leading to the crannog, which may have had a single large circular dwelling located on it.

No sign of the crannog is visible on the site today, however Buiston Loch is represented by a small area of permanent flooding and seasonal flooding extensions.