Ganesha Chaturthi is the Hindu festival celebrated on the birthday (rebirth) of Lord Ganesha, the son of Shiva and Parvati.
It is believed that Lord Ganesh bestows his presence on earth for all his devotees during this festival. It is the day when Ganesha was born. Ganesha is widely worshipped as the god of wisdom, prosperity and good fortune and traditionally invoked at the beginning of any new venture or at the start of travel. The festival, also known as Vinayaka Chaturthi (“festival of Ganesha”) is observed in the Hindu calendar month of Bhaadrapada, starting on the shukla chaturthi (fourth day of the waxing moon period). The date usually falls between 19 August and 20 September. The festival lasts for 10 days, ending on Anant Chaturdashi (fourteenth day of the waxing moon period).
While celebrated all over India, it is most elaborate in Maharashtra, Gujarat, Tamil Nadu, Goa, Andhra Pradesh, Karnataka, Odisha and Chhattisgarh. Outside India, it is celebrated widely in Nepal and by Hindus in the United States, Canada, Mauritius, Singapore, Malaysia, Thailand, Cambodia, Burma, Fiji, Trinidad & Tobago, and Guyana.
(data source: Wikipedia)