This was territory of the Abenaki tribe whose fortified village was located up the Sokokis Trail at Pequawket (now Fryeburg). The township was granted in 1630 by the Plymouth Company to Thomas Lewis and Richard Bonython, and extended 4 miles (6.4 km) along the sea, by 8 miles (13 km) inland. It was settled in 1631 as part of Winter Harbor (as Biddeford Pool was first known), it then included Biddeford. It would be reorganized in 1653 by the Massachusetts General Court as Saco.
The settlement was attacked by Indians in 1675 during King Philip’s War. Settlers moved to the mouth of the river, and the houses and mills they left behind were burned. Saco lay in contested territory between New England and New France, which recruited the Indians as allies. In 1689 during King William’s War, it was again attacked, with some residents taken captive. Hostilities intensified from 1702 until 1709, then ceased in 1713 with the Treaty of Portsmouth. The community was rebuilt and in 1718 incorporated as Biddeford. Peace would not last, however, and the town was again attacked in 1723 during Dummer’s War, when it contained 14 garrisons. In August and September 1723, there were Indian raids on Saco, Maine and Dover, New Hampshire, but in 1724, a Massachusetts militia destroyed Norridgewock, an Abenaki stronghold on the Kennebec River organizing raids on English settlements. The region became less dangerous, especially after the French defeat in 1745 at the Battle of Louisburg. The French and Indian Wars finally ended with the 1763 Treaty of Paris.
Inhabitants found the name Pepperrellborough to be cumbersome, so in 1805 it was renamed Saco. It would be incorporated as a city in 1867. Saco became a center for lumbering, with log drives down the river from Little Falls Plantation (now Dayton, Lyman, Hollis and part of Limington). Wood Island lighthouse is located off the entrance of Biddeford pool at the end of the Saco River.