Boac, a heritage town in its own right, is known as one of the main venues of the annual Moriones Festival and is the location of a number of historical sites in Marinduque including the Boac Cathedral fortress church, Casa Real and the Liwasan ng Kalayaan, Laylay Port, and the Battle of Paye site.

This is in reference to the town being bisected by the Boac River which runs from the Central Marinduque and Balagbag Mountain Ranges to the west coast facing the Tayabas Bay and Sibuyan Sea.

During the Spanish colonization, the first visita called Montserrat de Marinduque was established in the island in 1580 in what is now Boac.

In the early years of Spanish colonization in Marinduque, it was first mentioned in Miguel de Loarca's Relacion de las Yslas Filipinas (1582-1583) that the natives of the island are Pintados or tattooed people resembling those from the Camarines Provinces and the Visayan Islands.

In 1621, Spanish Jesuit missionaries brought a three-foot Marian image to Boac which will later be known as the Mahal na Ina ng Biglang Awa.

[6] In panic, the locals took refuge in the fortress church of Boac as able-bodied men defended the outer walls against the attacks.

According to legends, a very strong storm with torrential rain, thunder, and lightning engulfed the area and at its very height, it was reported that the image of a beautiful lady with outstretched arms appeared standing on the top of the fortress wall.

To commemorate this miracle, the old image brought by the Jesuits in Boac was placed in a shrine erected on the portion of the wall where Mary is said to have appeared.

Carmencita O. Reyes built a larger-than-life-size image of the Our Lady of Biglang Awa in cement and placed in the seashore in Balanacan Port to welcome travelers to the island.

The municipality is generally hilly, rugged and mountainous in the south and eastern part with thin strips of flat and farm lands and long shoreline in the west.

Many people stand on the bridge to watch the sun set and to get a good view of the Boac Cathedral.

Roman Catholicism is the major religion in Boac, with the see of the Diocese located in its town proper, the Immaculate Conception Cathedral.