Prior to Anglo-Dutch settlement, what is today Dutchess County was a leading center for the native Wappinger peoples. They had their council-fire at what is now present-day Fishkill Hook and also held gatherings along the Danskammer.
In 1683, the Province of New York established its first twelve counties, with Dutchess County being one of them. Its boundaries at that time included the present Putnam County, and a small portion of the present Columbia County (the towns of Clermont and Germantown). The county was named for Mary of Modena, Duchess of York, second wife of James, Duke of York (later James II, King of England).
Until 1713, Dutchess was administered by Ulster County.
In 1812, Putnam County was detached from Dutchess.
In the twelve years 1685-1697 lawful patents had been granted securing for their purchasers every foot of Hudson River shoreline in the original county. Three additional patents, to 1706, laid claim to the remaining interior lands.
From 1683-1725 most of the settlers in Dutchess County were Dutch. Many of these moved in from Albany and Ulster Counties. They settled along the Fishkill River and in the areas that are now Poughkeepsie and Rhinebeck.
From 1715-1730 most of the new settlers in Dutchess county were Germans. From 1730 until 1775 New Englanders were the main new settlers in Dutchess County.
Franklin D. Roosevelt lived in his family home in Hyde Park, overlooking the Hudson River.
In the 1960s G. Gordon Liddy (who went to prison for crimes committed during the Nixon administration's Watergate scandal and now a talk show host), was a Dutchess County assistant district attorney when he repeatedly tried to have Timothy Leary arrested on drug charges. By the 1980s, the two ex-cons went on a speaking tour together.
Prior to the 1960s, Dutchess County was primarily agricultural. Since then the southern part (from Poughkeepsie south) of the county has developed into a largely residential area, suburban in character, with many of its residents commuting to jobs in New York City. The northern region of the county is still very much rural with large farmlands but at the same time developed residences used during the summer and or on weekends by people living in the New York City urban area.