In Gaelic Ireland, Imbolc was the feis or festival marking the beginning of spring, during which great feasts were held. It is attested in some of the earliest Old Irish literature, from the 10th century onward. It was one of four Gaelic seasonal festivals: Samhain (~1 November), Imbolc (~1 February), Beltane (~1 May) and Lughnasadh (~1 August).

From the 18th century to the mid 20th century, many accounts of Imbolc or St Brigid’s Day were recorded by folklorists and other writers. They tell us how it was celebrated then, and shed light on how it may have been celebrated in the past. People making Brigid’s crosses at St Brigid’s Well near Liscannor
Imbolc has traditionally been celebrated on 1 February. However, because the day was deemed to begin and end at sunset, the celebrations would start on what is now 31 January. It has also been argued that the timing of the festival was originally more fluid and based on seasonal changes. It has been associated with the onset of the lambing season (which could vary by as much as two weeks before or after 1 February), the beginning of the spring sowing, and the blooming of blackthorn.
The holiday was a festival of the hearth and home, and a celebration of the lengthening days and the early signs of spring. Celebrations often involved hearthfires, special foods, divination or watching for omens, candles or a bonfire if the weather permitted. Fire and purification were an important part of the festival. The lighting of candles and fires represented the return of warmth and the increasing power of the Sun over the coming months. A spring cleaning was also customary.

Holy wells were visited at Imbolc, and at the other Gaelic festivals of Beltane and Lughnasa. Visitors to holy wells would pray for health while walking ‘sunwise’ around the well. They would then leave offerings, typically coins or clooties (see clootie well). Water from the well was used to bless the home, family members, livestock and fields.
Donald Alexander Mackenzie also recorded that offerings were made “to earth and sea”. The offering could be milk poured into the ground or porridge poured into the water, as a libation.