Era
20th century
108
19th century
38
Devonian
13
18th century
12
1858-1919
11
1865-1950
11
1951-
10
Revolution, 1775-1783
10
Colonial period, ca. 1600-1775
9
Cretaceous
7
1775-1865
6
1882-1945
6
1898-1951
6
1782-1862
5
21st century
5
Silurian
5
17th century
4
Civil War, 1861-1865
4
1757-1804
3
1775-1783
3
1884-1962
3
1933-1945
3
Pleistocene
3
To 1775
3
1592-1672
2
1697-1746
2
1752-1816
2
1783-1789
2
1801-1848
2
1815-1861
2
1820-1841
2
1822-1913
2
1827-1901
2
1865-1898
2
1881-1973
2
1882-1947
2
1892-1969
2
1908-1984
2
1928-2011
2
1942-
2
Mesozoic
2
Tertiary
2
To 1898
2
-1701
1
-1888
1
-1980
1
1580-1638
1
1620-1655
1
1639-approximately 1703
1
1656-1680
1
more ...