If you happen to arrive at your favorite state office on Monday only to find it closed, here’s why: a little-known holiday, Confederate Memorial Day, is commemorated in Alabama on the fourth Monday in April. This year, that date is April 25. The holiday is often observed in late April to mark the surrender of the last major Confederate field Army on April 26, 1865.

Alabama joins only two other states in marking a day to honor those who died in the Civil War as an official holiday. Mississippi holds the day on the last Monday of the month, and South Carolina observes the holiday on May 10.

Texas and Tennessee also commemorate the day, but not as state holidays. In Texas, there is Confederate Heroes Day on Jan. 19, and Confederate Decoration Day is observed on June 3 in Tennessee. Nearly 260,000 Civil War soldiers died in action.

On Confederate Memorial Day, all state offices, including courts, license and tag offices, are closed. Federal services, such as the U.S. mail, will operate. Federal offices, schools and banks will be open.

As for as other state-specific holidays in Alabama, we’ve already observed one, Robert E. Lee’s birthday on the third Monday in January (also observed that day: Martin Luther King Jr. Day), but we do have another on the horizon: Alabama will observe the birthday of Confederate President Jefferson Davis on the first Monday in June. Plan accordingly.