1609 French explorer Samuel de Champlain sails up the lake now bearing his name.
1731 The French begin construction of Fort St. Frederic in present day Crown Point.
1754 The French begin construction of Fort Carillon, later renamed Fort Ticonderoga by the British.
1759 French Troops abandon Forts St. Frederic and Carillon to the British, who begin construction of a new fortification at Crown Point.
1765 William Gilliland establishes Milltown on the banks of the Bouquet River in present day Willsboro.
1775 Fort Ticonderoga is captured from the British by a colonial militia under the command of Ethan Allen. The fort would be recaptured by the British two years later without a battle.
1776 Benedict Arnold's Lake Champlain fleet is destroyed, but the lateness of the season prompts the British to return to winter quarters in Canada.
1777 An army of approximately 8,000 men under the command of British General John Burgoyne set up along the Boquet River in Willsboro.
1777 Herrick's Regiment of Vermont rangers commanded by Captain Ebenezer Allen raids Gilliland's Willsboro settlement after Burgoyne's defeat at Saratoga, burning all structures that survived the British retreat up the lake.
1783 General George Washington visits the forts at Crown Point and Ticonderoga on an inspection tour with New York Governor George Clinton and Colonel Alexander Hamilton.
1790 The first federal census records 581 inhabitants in the towns of Crown Point and Willsboro, which were at that time part of Clinton County.
1794 A blockhouse is erected for the protection of the village of Essex. Never used in battle, the structure later served as the county's first courthouse and jail.
1799 Essex County is set off from Clinton County.
1807 A commission appointed by the state legislature determines the county seat should be moved from Essex to its present location in Elizabethtown.
1812 The state purchases land for the construction of an arsenal in Elizabethtown.
1813 British sailors attempting to seize supplies at Willsboro are driven back by the local militia.
1822 The boundaries of Essex County are fixed by an act of the state legislature.
1822 The state offers land grants in portions of Essex and adjoining counties to settlers who will clear and fence fifteen acres and erect a habitable dwelling within five years.
1832 The county's Board of Supervisors appropriates funds for the purchase of land and buildings to house the county's poor.
1837 The United States Government contracts with Peter Comstock to build a lighthouse at Split Rock in the town of Essex.
1838 The state arsenal in Elizabethtown is raided by local men in an attempt to provide arms to Canadian rebellionists.
1848 North Hudson is the last of Essex County's eighteen towns to be formally established.
1850 The population of Essex County surpasses 30,000 for the first time.
1872 Verplanck Colvin is appointed Superintendent of the Survey of the Adirondack Wilderness.
1885 New York State designates public land in the Catskills and the Adirondacks as a forest preserve.
1892 Governor Flower signs a bill creating an Adirondack Park.
1894 The "Forever Wild" clause prohibiting logging within the Forest Preserve becomes part of New York's Constitution.
1909 A public referendum returns the county seat to Elizabethtown following earlier votes by county supervisors to move the place of government to Westport and then to Port Henry.
1915 A portion of the border between Essex and Hamilton counties is redrawn by an act of the state legislature.
1924 The state legislature enacts a law restricting signs within the boundaries of the Adirondack Park. Within a year, the Conservation Commission removes over 1,300 signs.
1960 Construction of underground Atlas InterContinental Balistic Missle silos begins.
1971 The Adirondack Park Agency is created by the state to prepare a comprehensive land master plan and regulate private devlopment within the Adirondack Park.
1973 The boundaries of the Adirondack Park are expanded for a sixth time, bringing all of Essex County within the bound aries of the 9,262 square mile park.
1980 New York State creates the Olympic Redevelopment Authority.
2000 The population of Essex County reaches 38,851.