| 1/1/1966, Sat | New Year's Day |
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| 1/3/1966, Mon | New Year's Day: Additional Observance Day |
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| 3/3/1966, Thu | National Liberation Day |
- Note
- An official holiday commemorating the 3 March 1878 Treaty of San Stefano and Bulgaria's liberation from Ottoman rule.
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| 4/8/1966, Fri | Good Friday |
- Note
- An official holiday (Veliki petak / Orthodox Good Friday).
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| 4/9/1966, Sat | Holy Saturday |
- Note
- An official holiday (Velika sabota / Orthodox Holy Saturday).
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| 4/10/1966, Sun | Easter Sunday |
- Note
- An official holiday (Velikden / Orthodox Easter Sunday).
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| 4/11/1966, Mon | Easter Monday |
- Note
- An official holiday (Vtori den Velikden / Orthodox Easter Monday).
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| 5/1/1966, Sun | Labour Day |
- Note
- An official holiday (Den na truda). International Workers' Day.
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| 5/2/1966, Mon | Labour Day: Additional Observance Day |
- Note
- An official holiday (Den na truda). International Workers' Day.
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| 5/6/1966, Fri | St. George's Day / Bulgarian Armed Forces Day |
- Note
- An official holiday (Gergyovden). Commemorates St. George and the Bulgarian Armed Forces.
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| 5/24/1966, Tue | Day of Cyril and Methodius (Bulgarian Education/Culture) |
- Note
- An official holiday (Den na balgarskata prosveta i kultura). Commemorates Sts. Cyril and Methodius, creators of the Cyrillic alphabet.
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| 9/6/1966, Tue | Bulgarian Unification Day |
- Note
- An official holiday (Den na Saedinenieto). Commemorates the 6 September 1885 unification of the Principality of Bulgaria with Eastern Rumelia.
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| 9/22/1966, Thu | Bulgarian Independence Day |
- Note
- An official holiday (Den na Nezavisimostta). Commemorates Bulgaria's declaration of independence from the Ottoman Empire on 22 September 1908.
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| 12/24/1966, Sat | Christmas Eve |
- Note
- An official holiday (Badni Vecher / Christmas Eve).
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| 12/25/1966, Sun | Christmas Day |
- Note
- An official holiday (Rozhdestvo Hristovo / Christmas Day 1).
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| 12/26/1966, Mon | Christmas Eve: Additional Observance Day |
- Note
- An official holiday (Badni Vecher / Christmas Eve).
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| 12/26/1966, Mon | Christmas Day: Additional Observance Day |
- Note
- An official holiday (Rozhdestvo Hristovo / Christmas Day 1).
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| 12/26/1966, Mon | Second Day of Christmas |
- Note
- An official holiday (Christmas Day 2).
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