Yom Kippur, the holiest day in the Jewish New Year, is mentioned frequently in the AJHS archives. Of the many records where the holiday is mentioned, two of note are the Young Judaea Records in the Hadassah Archives, and the National Jewish Welfare Board (NJWB). Throughout the 20th and 21st centuries both organizations have been devoted to serving Jewish communities and preserving their legacies.
The Hadassah Archive documents the activities of Hadassah, the Women’s Zionist Organization of America, which funds health, counseling, and vocational training services for communities in Israel. Currently, Hadassah sponsors two Youth Aliyah villages in Israel, providing education, counseling, vocational training for jobs, and recreational programs in art, music, and sports. The organization also runs two hospitals, Hadassah Hospital Ein Kerem and Hadassah Hospital Mt. Scopus, which serve the people of Jerusalem.
This Yom Kippur excerpt from 1938 was chosen from the Young Judaea Records. In it, Yom Kippur is described as a day of atonement, which is observed by praying at a synagogue, fasting, and lighting a memorial candle on the night of Yom Kippur (referred to as Erev) in memory of departed loved ones.

The National Jewish Welfare Board was founded in 1917 to provide support for soldiers in wartime, during WWI and WWII. It later developed into an agency involved in all aspects of Jewish life in the United States and abroad. In 1990, the organization renamed itself as the Jewish Community Centers Association of North America.
This document from 1976 offers an FAQ of general questions about the High Holidays, including Yom Kippur, illuminating some holiday traditions and including advice and guidelines. This primary source from the NJWB archives equips people to be able to respectfully participate in observing Yom Kippur traditions.

AJHS wishes all a shanah tova!
View the National Jewish Welfare Board Records, I-337
View the Young Judaea Records in the Hadassah Archives I-578/RG 8