1780

Millennium: 2nd millennium
Centuries:
Decades:
Years:
September 21: American Major General Benedict Arnold, commander of West Point, commits treason by supplying information to Britain's Major John Andre.
1780 in various calendars
Gregorian calendar1780
MDCCLXXX
Ab urbe condita2533
Armenian calendar1229
ԹՎ ՌՄԻԹ
Assyrian calendar6530
Balinese saka calendar1701–1702
Bengali calendar1187
Berber calendar2730
British Regnal year20 Geo. 3 – 21 Geo. 3
Buddhist calendar2324
Burmese calendar1142
Byzantine calendar7288–7289
Chinese calendar己亥年 (Earth Pig)
4477 or 4270
    — to —
庚子年 (Metal Rat)
4478 or 4271
Coptic calendar1496–1497
Discordian calendar2946
Ethiopian calendar1772–1773
Hebrew calendar5540–5541
Hindu calendars
 - Vikram Samvat1836–1837
 - Shaka Samvat1701–1702
 - Kali Yuga4880–4881
Holocene calendar11780
Igbo calendar780–781
Iranian calendar1158–1159
Islamic calendar1193–1195
Japanese calendarAn'ei 9
(安永9年)
Javanese calendar1705–1706
Julian calendarGregorian minus 11 days
Korean calendar4113
Minguo calendar132 before ROC
民前132年
Nanakshahi calendar312
Thai solar calendar2322–2323
Tibetan calendar阴土猪年
(female Earth-Pig)
1906 or 1525 or 753
    — to —
阳金鼠年
(male Iron-Rat)
1907 or 1526 or 754
May 29: Waxhaw Massacre in America.

1780 (MDCCLXXX) was a leap year starting on Saturday of the Gregorian calendar and a leap year starting on Wednesday of the Julian calendar, the 1780th year of the Common Era (CE) and Anno Domini (AD) designations, the 780th year of the 2nd millennium, the 80th year of the 18th century, and the 1st year of the 1780s decade. As of the start of 1780, the Gregorian calendar was 11 days ahead of the Julian calendar, which remained in localized use until 1923.