Don’t miss the water-powered grist mill at Kykuit, the Rockefeller Estate. The estate, just 25 miles from New York City, is so immense one could spend a week taking the different tours. (Judy Crowell / Noozhawk photo)

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New York’s Hudson Valley extends 150 miles above the tip of Manhattan. National Geographic proclaimed it “one of the top 20 destinations in the world.” It’s vast, beautiful and legendary, and filled with limitless outdoor experiences and breathtaking places to visit. Here are three of my favorites.

When’s the last time you stayed in a castle? The Castle Hotel & Spa in Tarrytown, N.Y., is the perfect place to begin your exploration of the Hudson Valley. Built in 1897 by Howard Carroll, your first impression is of a Norman fortification in Wales or Scotland — exactly what he had in mind.

Situated atop the highest point in Westchester County and overlooking the Hudson River, it served as an observation post during World War II to monitor air traffic in the area. In 2013, it underwent a thorough renovation, including construction of THANN Sanctuary Spa, a state-of-the-art spa treatment center.

The Castle will pamper you in every way, from the culinary excellence of Equus to a feeling of being ensconced in a cherished family home — a castle home of unique old-world beauty and charm.

Charm oozes from the romantic, riverside home of Washington Irving, America’s first internationally famous author and creator of Rip Van Winkle and Ichabod Crane of The Legend of Sleepy Hollow. Considered one of the most authentic examples of mid-19th century life anywhere in the United States, he began building Sunnyside in 1835, wrapping it up in a wisteria vine. This vine is still growing, adding to the whimsy and mystique of Sunnyside.

He created a picturesque pond nearby, calling it “The Little Mediterranean,” and referred to his home as “his elegant little snuggery.” So filled with his aura and creativity, many have called Sunnyside a “three-dimensional autobiography.” Docents in hoop skirts of the time, master storytellers 19th century games and authentic puppet shows add to your visit.

Close by and as over-the-top grand as Sunnyside is quaint sits Kykuit, the Rockefeller Estate. This 40-room estate is operated and maintained by the Rockefeller Brothers Fund. Home to four generations of the Rockefeller family, Kykuit (Dutch for “lookout”) sits on the highest point of the Pocantico Hills, overlooking the Hudson River and just 25 miles from New York City, whose skyline can be seen on a clear day.

Family patriarch John D. Rockefeller hired landscape architect Frederick Law Olmsted of Central Park fame to design the unbelievably vast gardens. Unhappy with Olmsted’s designs, he took over the initial design and transplanting himself.

This estate is so immense one could spend a week taking the different tours. An oft-quoted witticism: “It’s what God would have built, if only He had the money.”

Don’t miss the cavernous coach barn with classic automobiles and horse-drawn carriages or the French Norman playhouse (for grownups) or the water-powered grist mill or renowned sculptures scattered throughout the terraced gardens or the lovely Union Church of Pocantico Hills about five minutes away, built by the family and featuring stained glass windows by Matisse and Chagall.

All this sightseeing will make you hungry. Some favorites are: Equus at the Castle Hotel & Spa, the Mint Premium Foods & Restaurant, Tarry Tavern, Sweet Grass Grill and The Twisted Oak — all in Tarrytown.

Like me, an advocate of travel in the United States, Irving once said: “No … never need an American look beyond his own country for the sublime and beautiful of natural scenery.” Case in point is the historic Hudson Valley.

— Judy Crowell is a Noozhawk contributing writer, author, freelance travel writer and Santa Barbara resident. She can be reached at news@noozhawk.com. The opinions expressed are her own.