The city derived its name from the word Bais, a fresh water eel that abundantly living in the place. According to the historians, when the Spaniards heard the fertile flatlands and rich in fishing grounds of the place they made an expedition led by a Spanish engineer to get the name of the area and pinpoint what is the exact location of the place and as well as to prepare the map of the island. When they arrived to the place, they saw some people in the mouth of the river catching on their net the so-called fresh water eel “Bais”, then the Spanish engineer asked a fisherman in a Spanish dialect “Como se llma este lugar?”, but the fisherman failed to understand, and only thinking that he was asked about the name of the fish they have caught, so the fisherman abruptly answered “Bais”. The Spanish engineer therefore expects that it was the name of the place.
After discovery of the island, many Spaniards travelled and settled in the area on the account of a good place and the fertility of the land. Some of them planted sugarcane and build sugar milled that produced “muscuvados” that came from the sugar cane. This is the start of the exportation of sugar to Spain via Iloilo, which then was the principal shipping point in the Visayas. The sugar was carried by a large boat called Lurcha or Batel during that time.
In 1850, Bais was a “visita” under the civil and ecclesiastical jurisdiction of the municipality of Tanjay, but in the years it became a barrio of Manjuyod and then separated itself into a Distrito Municpal.
On May 2, 1901 Bais became a Municipality, and was later declared a Chartered City on September 7, 1968 by virtue of RA 5444. The first municipal mayor that governs the town was Mayor Genaro Oni.
On September 9, 1968, before the declaration of Martial Law, Philippine President Ferdinand E. Marcos officially and personally proclaimed Bais as one city in the island of Negros.
The city was surrounded by two bays and the shoreline was mostly covered by mangroves, Bais City’s bays are popular and widely known for being one of the beautiful coral reefs in the Visayas Region.
The Pelarta River has been the source of irrigation water for the nearby sugar farms. This has been vital in the success of sugar plantations in this area. This river also has a big influence on the city’s geography, as it deposits sediments in the former mangrove areas during the (formerly annual) flood season. These former mangrove swamps have now dried out and become populated with residents. In the late seventies, under the government of Genaro Goni, there was established a river control system stretching from the city center towards the low lying areas in order to lessen flooding during the rainy season.
The Bais City was famous on its fiesta held every September 10, in honor of their Patron Saint Nicholas de Tolentino; this occasion was inherited from the Spanish era. During this celebration many events were being witnessed like street dancing, beauty contest and most of all, people prepared many foods for those persons who are visiting during this time. One of the most eye tourist attraction that many local and foreign tourist fond of, is the Dolphins that living in the deep water of the island. This attraction developed and increases the tourism rate of the city and provides them a good economic growth.