Many sources had cited 1907 as Sleeper's year of birth, but she was actually born shortly after the 1910 census was taken in April 1910. Martha's true date of birth is June 24, 1910, as verified by a copy of her birth certificate.
No "Martha Sleeper" appears in the 1910 census records; however, a "Martha Sleeper" is listed as 9 years old in the 1920 census (April 1920) and 19 years old in the 1930 census (April 1930). An airline passenger list, flight CBA 611 from St. Maarten to Charlotte Amalie, VI, on 10 Sep 1962, gives a birthdate of 6-24-1910, in Illinois (ancestry.com). A U.K. Incoming Passenger list (ancestry.com) for the RMS Queen Elizabeth, from New York to Southamptom, arriving 19 Aug 1958, gives a birthdate of 24.6.10. The Social Security Death Index records the date of birth of a "Martha Stelling" (Sleeper's third husband's surname) who died in March 1983 in Beaufort County, South Carolina as June 24, 1910. Sleeper's 1983 New York Times obituary, as well, was titled "Martha Sleeper Is Dead At 72."