The day originated in 1952 when Congress set aside the first Thursday in May for the observance and subsequent presidents publicly prayed, generally with Christian and Jewish observers.
Summary
1775 - The first Continental Congress called for a National Day of Prayer
1863 - Abraham Lincoln called for such a day.
1952 - Congress established NDP as an annual event by a joint resolution, signed into law by President Truman (82-324)
1988 - The law was amended and signed by President Reagan, designating the NDP as the first Thursday in May (100-307).
1. The President of the United States has called for a National Day of Prayer every year since 1975.
2. There have been 134 national calls to prayer, humiliation, fasting and thanksgiving by the President of the United States (1789-2008).
3. There have been 56 Presidential Proclamations for a “National Day of Prayer” (1952-2008).
4. Gerald Ford (1976) and George H. Bush (1989-91) are the only U.S. Presidents to sign two National Day of Prayer Proclamations in the same year.