Evergreen date guide

What is celebrated on April 11?

For 2026, these source-backed observances resolve to Saturday, April 11. Recurring rules can move in another year, so each record keeps its own date logic.

Date authority profile

What this date contains

12 unique authority records

The list is deduplicated at the public entity layer while retaining all research provenance behind each page.

0 stable or rule-calculated

0 fixed annual and 0 reusable rule-based records can be placed without inventing a new date.

0 edition-specific

Edition-specific dates appear only when the requested year matches the verified edition; variable and historical records remain gated.

5 explicit country-scope records

Country scope stays attached to the underlying record instead of being generalized into a worldwide observance.

0 reviewed in-depth guides

These entities add reviewed meaning, history, activities, facts and FAQs without rewriting the authority facts.

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Topics represented on April 11

All topics →

Arts, Entertainment & Lifestyle 3 Workplace, Professions & Appreciation 2 Food, Drink & Hospitality 2 Civic, Remembrance & History 1 Faith, Tradition & Spirituality 1 Celebrations & Social 1 Animals, Nature & Environment 1 Health, Wellness & Awareness 1

12 date-resolved records

All observances on this date

Source-backedFixed Annual

Dog Therapy Appreciation Day

11 April · Informal pet/therapy-animal appreciation calendar usage documented by a veterinary institution

The Animal Medical Center repeatedly lists Dog Therapy Appreciation Day on April 11 in annual pet-awareness calendars.

Source-backedFixed Annual

Día de la Batalla de Rivas

11 April annually · Costa Rica / statutory national commemoration

Costa Rica’s Legislative Assembly record for Act 8886 states that April 11 each year, the Day of the Battle of Rivas, is to be enjoyed and commemorated on the date itself.

Source-backedEdition Specific

Great and Holy Saturday

11 April 2026 · Orthodox Church in America / 2026 Holy Week

OCA’s daily readings identify 11 April 2026 as Great and Holy Saturday, the day before Pascha.

Source-backedFixed Annual

International Louie Louie Day

11 April in the organizer/community tradition; current activity should be rechecked yearly · Grassroots music/fan observance centered on the song “Louie Louie”

The Louie Louie advocacy/fan community documents International Louie Louie Day and its April 11 tradition, developed through the Louie Louie Advocacy and Music Appreciation Society ecosyste…

Source-backedFixed Annual

Marketing Operations Appreciation Day

11 April · Professional/workplace / Zapier-created Marketing Operations Appreciation Day

Zapier’s own 2023 campaign page states that Marketing Operations Appreciation Day is April 11 and describes it as an annual recognition initiative.

Source-backedFixed Annual

National Barbershop Quartet Day

11 April · Barbershop Harmony Society / organized barbershop commemoration

The Barbershop Harmony Society says National Barbershop Quartet Day commemorates the birth of the organized barbershop movement on 11 April 1938.

Source-backedFixed Annual

National Cheese Fondue Day

11 April · United States / informal food observance repeatedly promoted by The Melting Pot

The Melting Pot’s first-party 2025 material identifies April 11 as National Cheese Fondue Day, continuing a long-running brand celebration.

Source-backedFixed Annual

National Clean Up Your Pantry Day

11 April · United States / informal home-organization observance

National Today and Days Of The Year independently place National Clean Up Your Pantry Day on April 11 each year.

Source-backedFixed Annual

National Pet Day

11 April · United States-origin / creator-led pet observance with public-institution recognition

Founder Colleen Paige’s current holiday list places National Pet Day on April 11, and the U.S. Census Bureau lists National Pet Day on April 11 in its current April resources.

Source-backedFixed Annual

National Ranch Water Day

11 April · United States / RANCH2O Spirits-created beverage observance

RANCH2O Spirits publishes April 11 as National Ranch Water Day, and the National Day Archives registry states that April 11 is observed each calendar year and that RANCH2O created the day i…

Source-backedEdition Specific

Slow Art Day

11 April 2026; 3 April 2027 · Slow Art Day organizer / global museum and gallery event

The official Slow Art Day site lists 11 April for the 2026 edition and 3 April for 2027, directly showing that the event date changes by year.

Source-backedFixed Annual

World Parkinson's Day

11 April · Organizer-backed international observance

Parkinson's Europe and the international Parkinson’s community

How this date is built

This page is assembled from verified fixed dates, reusable recurrence rules, and target-year records whose edition matches 2026. Variable, historical or unresolved records are not silently forced onto this date.

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