PENINSULA Phippsburg

ust past Bath, Route 209 South twists by lobster shacks, aging boats in backyards, and flashes of salt marsh that expand into vast plains, greener than any field. And when the road takes a turn, there’s no major sign, more like a big roadside Post-It, announcing: Popham Beach State Park.

Certainly it’s no preparation for the Saharan plain of sand that shimmers and spreads for three fearless miles. A whistle shrieks and a lifeguard races by, frantically waving at four waders struggling to reach the temptingly nearby island, water swirling around their thighs. Fox Island Closed Due to Incoming Tides reads the sign they apparently ignored in the parking lot. Chastised, all turn back. Chunks of driftwood stumps lie strewn on the beach; the sand seems molded into tiny silent waves.

If you don’t know how to eat a lobster, Spinney’s Restaurant, three miles away in the shadow of Fort Popham, on the banks of the Kennebec River, offers an instruction chart. You can also absorb visual pointers on how to build a spectacular driftwood fence, which is all that separates us from the sand and water. Bathrooms are labeled Buoys and Gulls (“You want the mermaid, hon”); the wood interior is draped with sea paraphernalia; and the haddock chowder is addictively good. Chunks of fish, potatoes, and a reddish tang of paprika: A second cup feels inevitable.

Civil War–era Fort Popham is weird and wonderful, like the bottom half of a more modern-day Colosseum. All archways, tunnels, and half-moon curves, it’s a haunting relic that echoes with children’s shouts and offers shade to fishermen casting their lines. The view across the water to Georgetown foreshadows our next stop, which is another poetic truth of peninsulas: You’re always looking over to the next point of land.