Arbor Day was founded in 1872 by J. Sterling Morton in Nebraska City, Nebraska. By the 1920s, each state in the United States had passed public laws that stipulated a certain day to be Arbor Day or Arbor and Bird Day observance.

National Arbor Day is celebrated every year on the last Friday in April; it is a civic holiday in Nebraska. Other states have selected their own dates for Arbor Day.

The customary observance is to plant a tree. On the first Arbor Day, April 10, 1872, an estimated one million trees were planted.