Public holidays
1644, USA, Federal holidays
| # | Date | Public holiday |
|---|---|---|
| 1 | Friday, 1 January 1644 | New Year's Day |
| 2 | Monday, 18 January 1644 | Martin Luther King Day |
| 3 | Monday, 15 February 1644 | Washington's Birthday/Susan B. Anthony Day |
| 4 | Monday, 30 May 1644 | Memorial Day |
| 5 | Monday, 4 July 1644 | Independence Day |
| 6 | Monday, 5 September 1644 | Labor Day |
| 7 | Monday, 10 October 1644 | Columbus Day |
| 8 | Friday, 11 November 1644 | Veterans Day |
| 9 | Thursday, 24 November 1644 | Thanksgiving |
| 10 | Sunday, 25 December 1644 | Christmas |
| Monday, 26 December 1644 | Christmas (observance) |