United States federal executive departments - history

This list was pulled from here.

Compare this with the history of political realignments.

1789: State. 

1789 - 1947: War.

1789: Treasury.

1792 - 1971: Post Office.

1849: Interior.

1862: Agriculture.

1870: Justice.

1903 - 1913: Commerce and Labor.

1913: Commerce.

1913: Labor.

1947: Defense.

1953 - 1979: Health, Education, and Welfare.

1966: Housing and Urban Development.

1967: Transportation.

1977: Energy.

1979: Education.

1979: Health and Human Services.

1989: Veterans' Affairs.

2002: Homeland Security.