Wedged on a hillside between fertile Amazon wetlands and cerrado (dry scrub forest), the Monte Alegre area has long been a preferred site for human habitation. In the hills behind the town, carbon dating of middens below cave paintings indicates a human presence as many as 11,000 years ago, making them some of the earliest known in the Americas. A small band of Irish and English settled here in the 1570s, about 40 years before the Portuguese arrived in Belém. The site later became a missionary outpost—called Gurupatuba—for area natives. In 1758 it was incorporated as a village.
Today Monte Alegre is a city of around 80,000. Its economy relies mostly on ranching, farming, and fishing. The town obviously has a rich history, but it's not well organized for tourism. There's no town map, for example, and the streets are confusing. Also, visiting hours for the few historic sites change often if there are any. You can thoroughly enjoy Monte Alegre, however, if you walk around and talk to the locals. They're helpful and may go out of their way to assist you.