Era
20th century
104
21st century
63
19th century
40
18th century
12
Civil War, 1861-1865
10
1945-
8
1564-1616
7
1946-
7
1991-
7
2009-
7
Revolution, 1775-1783
7
1988-
6
Civil War, 2011-
6
Mesozoic
6
17th century
5
1897-1962
5
Carboniferous
5
Colonial period, ca. 1600-1775
5
Early modern, 1500-1700
5
1817-1862
4
1819-1891
4
1899-1961
4
1980-
4
Cretaceous
4
Eocene
4
Paleozoic
4
Precambrian
4
Tertiary
4
World War, 1939-1945
4
1685-1750
3
1843-1916
3
1873-1947
3
1874-1963
3
1902-1995
3
1917-1963
3
1933-1945
3
1936-2016
3
1945-1989
3
1965-
3
1986-
3
1993-
3
1997-
3
2001-2009
3
2003-
3
Early modern and Elizabethan, 1500-1600
3
Quaternary
3
To 1900
3
1588-1679
2
1608-1674
2
1643-1687
2
more ...