National Pet ID Week in US

Foursquare Day on April 16 (4sqDay or Foursquare Day was coined by Nate Bonilla-Warford, an optometrist from Tampa, Florida on March 12, 2010 being the 4th month and the 16th being equal to four squared. The idea came to him while "thinking about new ways to promote his business". FitBy4sqDay has been a quest by foursquare users to reach new fitness goals and live in a healthier way and is an excellent opportunity for local businesses to shine);

National Healthcare Decisions Day on April 16 (United States);

National Eggs Benedict Day, National Baked Ham with Pineapple Day and Day of the Mushroom in USA on April 16;

Stress Awareness Day on April 16;

Liberation Day in Washington, DC, USA on April 16 (in honor of a decree signed by President Abraham Lincoln in 1862 to free slaves from the District of Columbia);

National Tickle Day in USA on April 16;

National Cheeseball Day in USA on April 17;

Administrative Professionals Week in USA on April 17;

National Student Leadership Week in USA on April 17;

National Volunteer Week in USA on April 17;

Herbalist Day on April 17 (Herbal Academy of New England);

Animal Cruelty/Human Violence Awareness Week in USA on April 17 (Humane Society of the US – third week in April);

National Animal Crackers Day in USA on April 18;

Public School Volunteer Week in USA on April 18 (it provides a yearly opportunity for schools and families to honor and highlight the powerful contributions parents and caregivers provide at school and home to support student success. Held from Monday of the last full week of April);

National Lineman Appreciation Day on April 18;