[2] The village is 10 miles (16 km) southwest of Hagåtña,[3] with most of the residents ethnic Chamorros, the indigenous people of Guam.

In 1565, the Spanish explorer Miguel López de Legazpi claimed Guam for Spain.

Agat was founded between 1680 and 1684, by the Spanish Governor Don Jose Quiroga, as a military garrison for the purpose of controlling the Chamorro people and converting them to Christianity.

Many of its first citizens were brought from the internal village of Fina which was destroyed while the Spanish pacified the island.

During the 1830s, the Spanish Governor, Captain Villalobos, began constructing facilities in Agat planning to make it the island's new capital.

[8] Our Lady of Mount Carmel Catholic School is located in Agat and accommodates students in pre-kindergarten through eighth grade.