The 1940 Census was released recently and quickly indexed. It is available at FamilySearch.org (free) and Ancestry.com (for a fee).
Here are the United States 1940 Census records for my four grandparents. They were all still single and living at home in 1940.
Wallace Ove Tanner, age 15, St. Johns, Arizona
Jessie Maxine Morgan, age 14, 79 D Street, Salt Lake City, Utah
John Hayward Wessman, age 22, 184 E Street, Salt Lake City, Utah
Beverly Lucille Glade, age 15, 1421 Sherman Avenue, Salt Lake City, Utah