The United States has taken a national census every decade since 1790. Some states have done state censuses during non-federal census years. These are excellent resources for genealogists, and can reveal a lot of fascinating and new information about your ancestors. In fact, the census records are usually one of the first record sets new genealogists use in their research, as they are considered one of the most basic genealogy tools. The state censuses are useful for filling in the gaps in the federal census years, and for bridging the 20-year gap between the 1880 and 1900 federal census records since the 1890 census was destroyed in the 1930’s.