She studied at a girls’ boarding school

Eleanor moved to reside with her grandmother, Mrs. Valentine G. Hall, in Tivoli, New York, following the passing of her mother. Till the age of 15, she received private tutoring for her education. Eleanor began attending Allenwood, a ladies' boarding school outside of London when she was 15 years old. There, the French headmistress Marie Souvestre had an impact on Eleanor. At Allenwood, Eleanor was quite popular in addition to being very diligent, and many people think that her experience there helped her develop her confidence. Later, she claimed that Marie Souvestre was one of Eleanor's most significant role models and most influential persons.

Eleanor developed similar interests as a result of Souvestre's intellectual curiosity, her desire for adventure, and her pursuit of excellence—in everything but sports—and she later referred to her three years there as the happiest time of her life. To get ready for her "coming out" into a society that winter, she reluctantly went back to New York in the summer of 1902. She spent time volunteering in the community, including teaching in a settlement house on Manhattan's Lower East Side, as per family tradition. Even though Eleanor didn't attend college, Allenwood offered a serious university atmosphere with high academic expectations.