Era
20th century
73
Civil War, 1861-1865
73
19th century
48
Revolution, 1775-1783
45
1809-1865
25
1945-1989
24
1732-1799
21
Colonial period, ca. 1600-1775
20
1861-1865
19
1933-1945
19
1783-1865
15
1882-1945
15
18th century
12
1945-
12
1775-1783
11
1917-1963
11
1989-
10
1945-1953
9
1865-1918
8
1929-1968
8
1969-1974
8
1706-1790
7
1743-1826
7
1775-1865
7
1818-1895
7
1877-1964
7
1913-1994
7
1946-
7
1961-1963
7
1975-
7
1977-1981
7
1981-1989
7
1863-1877
6
1865-1877
6
1884-1972
6
1918-1945
6
1953-1961
6
2001-2009
6
To 1964
6
1750-1815
5
1856-1924
5
1858-1919
5
1865-1898
5
1913-1921
5
21st century
5
To 1863
5
1735-1826
4
1767-1845
4
17th century
4
1815-1861
4
more ...