The parish is bordered by Trelawny in the east, St. Elizabeth in the south and Hanover and Westmoreland in the west. It covers an area of 594.9 km², making it one of the smallest parishes in Jamaica. The population was 184,662 in 2012. About two-thirds of the parish consists of limestone. The Nassau Mountains, which rise from St. Elizabeth, south of the parish, extend diagonally across St. James. The range then declines to a point just south of Montego Bay. Its highest point is approximately 1524 metres above sea level.
When the Spanish occupied Jamaica, Montego Bay was an export point for lard, which was obtained from wild hogs in the forests. In many of the Jamaica's early maps, Montego Bay was listed as "Bahia de Manteca" (Lard Bay). The parish was given the name "St. James" in honour of King James II by Sir Thomas Modyford, the island's first English Governor. At the beginning of the English rule, the parish was one of the poorest; it had no towns, few inhabitants and little commerce, except for the exported lard. However, after the treaty with the Maroons in 1739, St. James became one of the most important sugar-producing parishes. Annually, more than 150 ships arrived in Montego Bay bringing slaves and supplies, and taking sugar. Commerce developed as wealthy merchants and planters erected many elaborate town houses. In 1773, Montego Bay had the only newspaper outside of Kingston - The Cornwall Chronicle.
When Christopher Columbus for the first time visited the island in 1494, he named the bay Golfo de Buen Tiempo ("Fair Weather Gulf"). The name "Montego Bay" is believed to have originated as a corruption of the Spanish word manteca ("lard"), allegedly because during the Spanish period it was the port where lard, leather, and beef were exported. Jamaica was a colony of Spain from 1511 until 1655, when Oliver Cromwell's Caribbean expedition, the Western Design, drove the Spanish from the island. During the epoch of slavery, from the mid-17th century until 1834, and well into the 20th century, the town functioned primarily as a sugarcane port. The island's last major slave revolt, the Christmas Rebellion or Baptist War (1831–1832) took place in the area around Montego Bay; the leader of the revolt, Samuel Sharpe, was hanged there in 1832. In 1975, Sharpe was proclaimed a national hero of Jamaica, and the main square of the town was renamed in his honor.