The nine rocky islands scattered just off of Portsmouth Harbor have long fascinated and beguiled residents. In fact, they were used for fishing grounds by European explorers for years before the Pilgrims landed in 1620. The name “shoals” doesn’t refer to shallow water, but the “schools” of fish that would congregate here around upwellings of nutrients from the islands’ unusually deep waters.

Over the years the islands were home to a thriving community of fishermen and merchants. They achieved wider fame, however, when two grand hotels were built on Star and Appledore Islands to receive the rich and powerful of Boston society. The daughter of one of the hotel owners, poetess Celia Thaxter, added to the islands’ allure with a bestselling 1873 book called Among the Isles of Shoals, which was filled with tales of ghosts, shipwrecks, and legends of Blackbeard’s buried treasure.

Not that she had to make much up—the islands’ most famous incident came that same year, in 1873, when two sisters were brutally murdered by an axe-wielding itinerant fisherman on the island of Smuttynose. A third woman managed to elude the killer and bring him to justice, but the story continues to haunt the area, with the most recent adaptation being Anita Shreve’s novel The Weight of Water, later made into a film with Sean Penn and Elizabeth Hurley.

Tours of the islands with the Isles of Shoals Steamship Company (315 Market St., Portsmouth, 603/431-5500 or 800/441-4620, www.islesofshoals.com, 8 a.m.–7 p.m. mid-June–Labor Day, 9 a.m.–4 p.m. fall and spring, 10 a.m.–2 p.m. winter, several tours daily, prices vary) take advantage of all of the mist-enshrouded legends in guided cruises laden with history and lore.

Perhaps just as satisfying, however, is to explore the islands yourself, taking a ferry with Island Cruises (Rye Harbor State Marina, Rte. 1A, Rye, 603/964-6446, www.uncleoscar.com) to Star Island to visit the grand Star Hotel and hike the surf-sprayed trails and ledges. That company also offers tours of the island that are a bit more intimate than the Steamship Company, which fosters a reputation as a “party boat.”