The National Park Service is celebrating its centennial in 2016 and festivities will get underway at the Weir Farm National Historic Site in Wilton, on the Ridgefield border, Sunday, May 1, from 10 to 4, when the visitors center and museum store, house, studios, barns and outbuildings, a total of 16 structures, open for the season. They will remain open through Oct. 31, and ranger-led tours are conducted at 11, 1, 2 and 3, Wednesday through Sunday.

The gently rolling, scenic grounds of the 60-acre historic site — named for American Impressionist Julian Alden Weir, the first in the National Park System to honor an American painter, and dedicated to the visual arts — are open year-round from sunset to sundown. Visitors are welcome to walk around and make art at their leisure. The landscape includes stone walls, gardens, woods, open fields, a stream and a pond.

Park brochures, including a painting sites guide and self-guided tour, Junior Ranger activities, and a National Park passport stamp are always available on the covered porch of the visitors center.

On Saturday, May 21, Weir Farm will be part of BioBlitz, a joint effort of the National Park Service and National Geographic Society to compile a national inventory of the things that grow and live in the nation’s parklands. Jean Mackay is coordinating the effort at Weir Farm, which also happens to be National Kids to Parks Day. “This is a great opportunity for individuals, friends and families to explore and discover things that are of interest to them,” she said.

“The event will run from 8 a.m. to 3 p.m. and we urge everyone to participate, whether for an hour or all day. Visitors will meet and work with scientists to find and record species of plants and wildlife. You can choose what you want to look for — wildflowers, birds, insects, specific animals or plants, and so on, all of which will be added to a master inventory of the property and shared with a national database.”

There will also be an art tent with a variety of activities all day, as well as an installation of life-size cutout bison — the symbol of the National Park Service, and each covered with a historic painting related to Weir Farm — scattered throughout the park for discovery. There are seven large bison and three calves to be found.

One hundred ways to explore the park are being offered throughout the year, 25 for each season. Four pieces of Weir’s art from a private collection, which are rarely exhibited, will be on display through October.

Art supplies, including watercolors, pastels and pencils, are always available for people to try things, Mackay noted, adding, “We want our visitors to go out and experience the site; this is your park, please use it. It’s a great place for families and kids, the marriage of art to nature. We offer a Junior Ranger program for kids, as well as letterboxing, better known to some as treasure hunts.”

Additionally, art classes are offered for children as well as adults.

Michelle Stewart, centennial volunteer ambassador at Weir Farm National Historic Site, has put out the call for volunteers for the upcoming season, saying, “This is an exciting time at Weir Farm National Historic Site, as we prepare to celebrate the centennial year of the National Park Service. The past few years have been monumental for the park and this year is no different. Our historic buildings opened to the public fully restored and furnished for the first time in the park’s history in 2014 and last year we celebrated our 25th anniversary, and we cannot wait to share what we have in store to celebrate the 100th anniversary of the National Park Service.

“Volunteer opportunities include providing interpretation of our two historic art studios as studio docents, assisting our Natural Resources division as a member of the Garden Gang, providing art supplies and assistance as a Take Part in Art volunteer, and providing reports on current trail conditions as a trail monitor.”

Admission is free at Weir Farm, and Military, Access and Senior Passes can be obtained on site. All passes provide some discounts at other parks with fees to qualifying U.S. citizens or permanent residents. The Access Pass is provided free to those with permanent disabilities, while the lifetime Senior Pass is available to those 62 and older for a $10 fee. If obtained by mail with a form printed out from the Park Service website (nps.gov), the latter two passes have a $10 processing fee.

Weir farm also has a year-round artist-in-residence program, where artists live and paint on the property for about a month at a time. The April artist, Michele Schuff from Atlanta, says obtaining a residency is like “going to heaven. It is a dedicated time to make art.” Visiting the Northeast for the first time, she finds the area “absolutely beautiful — and so quiet.”

For those who follow the sign for Weir Pond, the gradual downhill walk on a well-marked trail takes about 10 minutes, and the loop around the pond itself is a mile. Leashed pets are welcome and a bike rack is adjacent to the small parking lot across the road from the visitors center.

The farm’s Weir

Julian Alden Weir, a leading figure in American art and the development of American Impressionism, acquired the then 253-acre farm in 1882 where he was joined by such famous contemporaries as Childe Hassam, John Twachtman and Albert Pinkham Ryder — to paint the landscape en plein air and experiment with light and color to create American masterpieces. After Weir, the artistic legacy was continued by his daughter, painter Dorothy Weir Young and her husband, sculptor Mahonri Young, followed by New England painters Sperry and Doris Andrews, who were there until 2005.

Weir Farm was designated a national park 1990.

The National Park Service was created by an act signed by President Woodrow Wilson on August 25, 1916. Yellowstone National Park was established by an act signed by President Ulysses S. Grant on March 1, 1872, as the nation’s first national park.

Weir Farm National Historic Site is at 735 Nod Hill Road, Wilton. To volunteer or for additional information, nps.gov/wefa or 203-834-1896.