Ilinden, celebrated on August 2 according to the old calendar, honors the Holy Prophet Elijah. Recognized by Christians as one of the greatest biblical prophets, Elijah is also considered one of the two most significant figures of the Old Testament, alongside Moses. In Bulgarian folklore, he is envisioned as flying in a fiery chariot across the skies and wielding his whip over galloping horses.

Traditionally, Ilinden is marked by refraining from work to avoid angering Saint Elijah, who is revered as the lord of thunder and hail. On this day, people make sacrifices for health and organize large village gatherings and celebrations. There is a belief that the sea claims the most victims on this day, and if thunder occurs, walnuts and hazelnuts will be hollow and rotten.

August 2 also commemorates the Ilinden-Preobrazhenie Uprising in Bulgaria, a pivotal event in the national liberation movement of the Macedonian and Thracian Bulgarians. The uprising, orchestrated by the Internal Macedonian-Odrina Revolutionary Organization (IMORO), began on August 2 (new style) in 1903 in Macedonia and on August 19 (new style) in the Odrin (Edirne) region. It marked a significant moment in the struggle for liberation, with around 30,000 people fleeing to Bulgaria due to the suppression of the uprising.

In Bulgarian folk tradition, Ilinden is one of the major summer holidays celebrated during the harvest and threshing season. It is believed that from this day onward, the weather begins to shift, with autumn winds starting to blow, and the sea becomes more treacherous with waves and strong currents.

Today, name days are celebrated by those named Ilia, Ilian, Iliana, Iliko, Ilina, Ilka, Ilyana, Elian, Elin, Lilo, Lilcho, Licho, Lilya, Lino, and Liljo.