Casco is a town in Cumberland County, Maine, United States. The population was 3,742 at the 2010 census. Casco includes the villages of Casco, South Casco and Cook Mills. The town borders the east shore of Sebago Lake, and is home to part of Sebago Lake State Park. Casco is part of the Portland–South Portland–Biddeford, Maine metropolitan statistical area. Casco is just under from downtown Portland.
Casco is the home of "Casco Days", an annual community fair which takes place in Casco Days Park, always on the last Saturday in July.
On January 30, 1767, Raymondtown Plantation was granted by the Massachusetts General Court to Capt. William Raymond of Beverly, Massachusetts and his company of soldiers for their service with Sir William Phipps in the 1690 Battle of Quebec. It replaced a 1735 grant called Beverly-Canada (now Weare, New Hampshire) which was ruled invalid in 1741 because of a prior claim by the heirs of John Mason. In 1803, Raymondtown Plantation was incorporated as Raymond. The town of Naples was created with land taken in 1838, the same year the western half of Raymond petitioned the legislature to be set off as a township because of its geographical separation behind Rattlesnake Mountain. The petition failed, but three years later another was accepted. On March 18, 1841, Casco was incorporated as a town.
Farmers found the surface of the town uneven, its hard and rocky soil "tolerably productive." Outlets of ponds, however, provided Casco with good sites for water powered mills. The town had four sawmills, four gristmills, a shook mill, a barrel stave mill, four shingle factories, a carriage factory and a tannery. In 1832, the Cumberland and Oxford Canal made Sebago Lake a direct trade route to Portland. Steamboat travel commenced on the waterways in the 1840s, carrying tourists and freight. In 1938, Sebago Lake State Park was established, one of the state's five original state parks.