Sebago Lake

Sebago is the lake Portland drinks from — literally. The Portland Water District draws from it for about 20 percent of Maine's population, and the watershed stays clean enough that the water needs almost no filtration, one of a handful of surface systems in the country with that exemption. It's also the state's deepest lake, dropping past 300 feet in the main basin. None of that shows up on the surface at Naples, where the Causeway carries the lake's whole social life across the bridge between Long Lake and Brandy Pond: ice cream stands, Rick's Cafe in the old 1901 Casino building, and the Songo River Queen II, a 93-foot paddlewheeler that runs through the hand-operated Songo Lock — the last surviving hand-cranked lock on the old Cumberland and Oxford Canal. Raymond and Casco hold the quieter eastern and northern shore, with Loon Echo Land Trust preserves filling in the hiking the lake itself doesn't have much of. Standish and the town of Sebago cover the south and west shore, more marina than restaurant row. Windham, inland on Route 302, carries the real infrastructure. Thirty to forty minutes from Portland puts the whole lake in range for a weekend, which is most of why Boston and Portland buyers treat this as real second-home territory. Frye Island, reachable only by seasonal car ferry, is the outlier — a private, golf-cart island community that closes down entirely once the ice gets too thick to run the boat.