·        1790, 1800, 1810 – Apparently the 1st Monday in August

·        1820 – 1st Monday in August (August 7th)

·        1830, 1840, 1850, 1860, 1870, 1880, 1890, 1900 – June 1st

·        1910 – April 15th

·        1920 – January 1st

·        1930, 1940, 1950, 1960, 1970, 1980 – April 1st

From "Unpuzzling Your Past: the best-selling guide to genealogy" by Emily Anne Croom.