Question: In which year was the historic house and museum that the Maine Historical Society operates from designated as a National Historic Landmark?

Context articles: John A. North House
Riley Lucas Bartholomew House
F. Julius LeMoyne House
Peter Kremer House
Simon Cameron House
Mercer Museum
Ashbel Woodward House
Maine Historical Society
Wadsworth-Longfellow House
Rensselaer County Historical Society

The John A. North House is a historic house museum and archives located in Lewisburg, Greenbrier County, West Virginia.
 Currently, the North House is Greenbrier County's only historic house museum.
 Since 1976, The Greenbrier Historical Society has operated within the North House, and in 1992 the North House was officially purchased by the Greenbrier Historical Society.
 In 1992, the home officially became known as " North House Museum, Greenbrier Historical Society."
The Riley Lucas Bartholomew House is a historic house museum in Richfield, Minnesota, United States, originally the home of prominent early Minnesotan Riley Bartholomew (1807–1894).
 The Richfield Historical Society operates the house as the Bartholomew House Museum adjacent to their Richfield History Center.
The F. Julius LeMoyne House is a historic house museum at 49 East Maiden Street in Washington, Pennsylvania.
 Built in 1812, it was the home of Dr. Francis Julius LeMoyne (1798–1897), an antislavery activist who used it as a stop on the Underground Railroad.
 LeMoyne also assisted in the education of freed slaves after the American Civil War, founding the historically black LeMoyne–Owen College in Memphis, Tennessee.
 His house, now operated as a museum by the local historical society, was designated a National Historic Landmark in 1997.
 It is designated as a historic public landmark by the Washington County History & Landmarks Foundation.
The Peter Kremer House is a historic house museum in Minnesota Lake, Minnesota, United States.
 The Minnesota Lake Historical Society operates the house as the Kremer House Library and Museum.
The Simon Cameron House, also known as John Harris Mansion and the Harris-Cameron Mansion, is a historic house museum at 219 South Front Street in Harrisburg, Pennsylvania.
 Built in 1766 and frequently extended and altered, it is one of Harrisburg's oldest buildings, and is nationally notable as the summer residence of Simon Cameron (1799-1889), an influential Republican Party politician during and after the American Civil War.
 The house and family items were donated to the Historical Society of Dauphin County in 1941, which now operates it as a museum.
 The mansion was declared a National Historic Landmark in 1975, and is located in the Harrisburg Historic District.
The Mercer Museum is a museum located in Doylestown, Pennsylvania, United States.
 The Bucks County Historical Society operates the Mercer Museum, as well as the Research Library, and Fonthill Castle, former home of the museum's founder, archeologist Henry Chapman Mercer.
 The museum was individually listed on the National Register of Historic Places in 1972, and was later included in a National Historic Landmark District along with the Moravian Pottery and Tile Works and Fonthill.
 These three structures are the only poured-in-place concrete structures built by Mercer.
The Ashbel Woodward House is a historic house museum at 387 Connecticut Route 32 in Franklin, Connecticut.
 The house is now operated by the Town of Franklin as the Dr. Ashbel Woodward House Museum.
 It is a 2-1/2 story wood frame structure, five bays wide, with a side gable roof, clapboard siding, a granite foundation, and a pair of brick chimneys.
 The museum features exhibits on local history and an art gallery.
 The main entrance is centered on the front, slightly recessed under a Greek Revival surround with pilasters and entablature.
 The building corners are also pilastered, and the side gable ends have semi-elliptical windows.
 An ell, apparently original as it shares the foundation with the house, extends to the rear.
 The property also includes two barns and a third outbuilding that probably functioned as a corn crib.
 The house was built c. 1835, and is a fine local example of a Greek Revival house in a rural setting.
 It was home for many years to Ashbel Woodward, a local doctor.
 His descendants gave the property to the state in 1947.
 The house is now owned by the town, whose historical society operates it as a local history museum.
The Maine Historical Society is the official state historical society of Maine.
 It is located at 489 Congress Street in downtown Portland.
 The Society currently operates the Wadsworth-Longfellow House, a National Historic Landmark, Longfellow Garden, the Maine Historical Society Museum and Store, the Brown Research Library, as well as the Maine Memory Network, an online database of documents and images that includes resources from many of state's local historical societies.
The Wadsworth-Longfellow House is a historic house and museum in Portland, Maine, United States.
 It is located at 489 Congress Street and is operated by the Maine Historical Society.
 It was designated a National Historic Landmark in 1962, and administratively added to the National Register of Historic Places in 1966.
 The house is open daily to public from May through October (half days on Sundays).
 An admission fee is charged.
The Rensselaer County Historical Society (RCHS) is a non-profit, historical society and museum, to promote the study of the history of the Rensselaer County, NY.
 RCHS was founded in 1927, and originally operated out of a single room in the Troy Public Library, collecting manuscripts and published materials related to the county's history.
 It is located in the Central Troy Historic District, in Troy, NY.
 The Rensselaer County Historical Society operates a museum, and offers public programs from its location at 57 Second Street, Troy, NY.