National Day of Encouragement in United States

Emergency Number Day on September 11 (United States);

National Day of Service and Remembrance in United States on September 11 (September 11 attacks-related observances);

National Hot Cross Bun in USA on September 11;

Stand Up To Cancer Day in US on September 11 (Held on the second Friday of September);

Defenders Day on September 12 (Maryland, United States);

National Chocolate Milkshake Day on September 12 (United States);

Video Games Day on September 12 (The Nimrod was a computer built and displayed at the Festival of Britain in 1951 and designed to play a game called Nim);

World Headache Day on September 12 (A Day of Awareness and Support);

National or International Chocolate Day on September 13 (United States, the U.S. National Confectioners Association);

National Celiac Awareness Day on September 13 (The United States Senate has once again designated September 13th as "National Celiac Awareness Day." According to the resolution, the Senate "recognizes that all people of the United States should become more informed and aware of celiac disease" and encourages all Americans to participate in activities that celebrate this day. Celiac disease affects an estimated 3 million Americans, 85% of whom remain undiagnosed or misdiagnosed);

National Peanut Day in USA on September 13;

National Pet Memorial Day in US on September 13 (Second Sunday of September);

Uncle Sam Day on September 13;

Grandparents Day in United States on September 13 (1978);

National Arts in Education Week in US on September 13 (takes place annually during the week beginning with the second Sunday of September);

Pet Birth Defect Awareness Day on September 13;

National Truck Driver Appreciation Week in USA on September 13 (Held from the second Sunday in September);