American Art Week is underway in New York City where historical and modern works get the limelight at galleries, museums and auction houses. Here are a few highlights:

1. Just Off Madison. This annual event is an open house at leading private American art galleries on May 18, from 10am-2pm. Stroll along the Upper East Side and enjoy viewing fine examples by seminal American artists.

A few special exhibitions to note: Jonathan Boos has a John Singer Sargent and also on view Side-by-Side: American Modernist Pairings, featuring works by John Atherton, Albert Bierstadt, Stuart Davis, Arthur Dove, Philip Evergood, Sanford Robinson Gifford, Jacob Lawrence, Hughie Lee-Smith, Norman Lewis, John Marin, George L.K. Morris, Frederic Remington, Ben Shahn, Charles Sheeler and Helen Torr, among others.

MME Fine Art is showing a trove of exquisite paintings by Jessie Arms Botke, known especially for her sumptuous renditions of peacocks and other highly decorative bird studies, dating from the early 20th century.

2. The Jack Warner Foundation collection at Questroyal Fine Art. An exhibition and sale of paintings from this distinguished private collection of American art is an opportunity to acquire works by the likes of Albert Bierstadt, William Merritt Chase, Childe Hassam, Winslow Homer, James Abbott McNeill Whistler, and Andrew Newell Wyeth. Alabama businessman Jack Warner collected with an expert eye for over 40 years, acquiring some of the best-of-the-best examples in American art. While masterworks have been sold in the recent past, much of the finest culled from Warner's collection is now offered. Catalog is here.

3. Christie's has a few Modernist stand-outs in its 95-lot American art sale on May 19. One highlight is a Georgia O'Keeffe titled Lake George Reflection, a virbrant horizontal landscape that can be turned vertically to become a cool abstraction. The estimate is $8 million to $12 million. There is also a fresh-to-market Alfred Jacob Miller, Pawnee Running a Buffalo, its first time emerging from private hands since 1854. It could bring more than $1 million.

4. Sotheby's headlines its American art sale on May 18 with a vivid Poppies painting from 1886 by John Singer Sargent. A study for the Impressionist's masterpiece Carnation, Lily, Lily, Rose, his Poppies is estimated to fetch as much as $4 million to $6 million. There are also prime examples by Rockwell, Wyeth and O'Keeffe in the 65-lot sale as well as small-sized "classics" by Peto and Heade and a lively Hayley Lever of Dancing Boats Marblehead, estimated at $50,000-$70,000.

5. Collectors, dealers and museum professionals can get a 2-day educational intensive at the Graduate Center of the City University of New York which hosts Initiatives in Art and Culture. This year's conference explores "To See Anew: Experiencing American Art in the 21st Century." Presenters include leading scholars, specialists and curators in American art, from May 20-21.

Coming up: On June 10, Stuart Davis: In Full Swing opens at the Whitney. Swann Galleries' American art sale is on June 9.