Winterport is a town in Waldo County, Maine, United States. The population was 3,757 at the 2010 census.
First settled in 1766 as part of Frankfort, it was set off and incorporated on March 12, 1860. It was named Winterport because of its fine harbor on the Penobscot River estuary, which generally remained ice free, and so became a busy local terminus for trade and shipping during winter months. When the upper Penobscot River froze, commodities like flour were hauled in large quantities from here to Bangor.
In 1841, Theophilus Cushing opened a large steam mill which manufactured 11,000,000 feet of lumber annually. It also made sugar box shooks, lath, clapboard, and soap and candle boxes. The town had two cooperage factories. Other industries produced harnesses, cheese and butter, and men's vests. Until the Panic of 1857, Winterport was a shipbuilding center. But the principal business for most of the town was agriculture.
According to the United States Census Bureau, the town has a total area of 37.05 square miles (95.96 km2), of which, 35.52 square miles (92.00 km2) of it is land and 1.53 square miles (3.96 km2) is water.