Bridget of Ireland died on February 1, 523, at Kildare, Ireland, of natural causes. When the date a saint died is known, that is frequently used as the feast date but that is not a rule carved in stone. Any date may be chosen. Remember, there are more than ten thousand named saints and only 365 days in a year.
That depends on which Bridget you mean. Saint Bridget of Sweden's feast day is July 23. Saint Brigid of Ireland's feast day is February 1.
Saint Brigid was an Irish saint, from county Kildare in Ireland. She is the patroness of Ireland, in the same way that Saint Patrick is the patron saint. Her feast date is the 1st of February.
The feast day of Saint David is the 1st of March
June 1st is the feast day of St. Justin the Martyr.
The feast of St. Brigid falls on February 1st, the day of her death and the traditional 1st day of spring in Ireland. Some speculate that Brigid was also a pagan goddess and so coincedentally, Feb. 1st is a pagan/Wiccan "cross quarter day" (or holy day) referred to as Imbolc and is related to St. Brigid in 1 way or another. So the feast day for Brigid the Saint and Brigid the Goddess is Feb. 1st either way.
St. David's feast day is March 1st as per the Patron Saint Index.
All Saint's Day is November 1st, but the list of Saints that have their feast days celebrated in the month of November are on this website in the related links below.
The feast of St. Meigan (Megan) the monk is on October 17.
Along with St. Patrick, she is a patron saint of Ireland. She is known for convents she founded, for her love of wildlife and the making of the St. Brigid's Cross. Her feast day is the 1st of February.
Most feast days are celebrated with a Mass in honor of that saint. If you want to know about local customs, you need to be more specific, as in, "How is St. David's feast day celebrated in Wales?"
The feast of Saint David of Wales is on March 1st. Since neither his date of birth or date of death is known, it is not possible to link March 1 with his birthday.
In the Western World it is on 2nd January; in the Eastern Orthodox Calendar it is January 1st, our New Year's Day.