|Covid-19|February 4 – Prince Bethlen Gabor signs a peace treaty with Ferdinand II, Holy Roman Emperor.
May 17 – The first merry-go-round is seen at a fair (Philippapolis, Turkey).
June 3 – The oldest stone church in French North America, Notre-Dame-des-Anges, is begun at Quebec City, Canada.
July 3 – Under the terms of the Treaty of Ulm, the Protestant Union declares neutrality and ceases to support Frederick V of Bohemia.
July 15 – The ship Speedwell departs Delfshaven with the Leiden colonists and Pilgrims.
August 5 (O.S.) – Mayflower and Speedwell depart together from Plymouth, England, but Speedwell starts to leak again and must stop.
The mother of Johannes Kepler is arrested for witchcraft.
Battle of Les Ponts-de-Cé, Poitou: French king Louis XIII defeats his mother Marie de' Medici.
August 8 – Mysterious rain of frogs in Weil der Stadt.
August 14 The Battle of the Yellow Ford in Ulster, Ireland saw the Irish forces of Hugh O'Neill, Earl of Tyrone ambush and annihilate the English forces of Henry Bagenal.
September 6 (O.S.) – Mayflower departs from Plymouth, England, on its 3rd attempt without Speedwell, arriving on November 11 (Old Style date) at Cape Cod (named from Concord voyage of 1602).
September 17–October 7 – Battle of Cecora: The Ottoman Empire defeats Polish–Lithuanian Commonwealth–Moldavian troops.
October 6 – The Roman Catholic Ras Sela Kristos, half-brother of the Emperor Susenyos crushes a group of rebels in at Mount Amedamit in Gojjam, Ethiopia, who were opposed to Susenyos' pro-Catholic beliefs.
November 3 – The Great Patent is granted to Plymouth Colony.
November 8 – Thirty Years' War – Battle of White Mountain: Catholic forces are victorious in only two hours near Prague.
November 21 (November 11 O.S.) – The Mayflower arrives inside the tip of Cape Cod at what becomes known as Provincetown Harbor, with the Pilgrims and Planters. 41 Plymouth Colony settlers sign the Mayflower Compact, the first governing document of the colony, onboard the ship.
November 25 – Wedding of Gustav II Adolf and Maria Eleonora
December 21 – Plymouth Colony: William Bradford and the Mayflower Pilgrims land on what becomes known as Plymouth Rock in Plymouth, Massachusetts.
A severe frost in England, with the Thames frozen. 13 continuous days of snow in Scotland. On Eskdale Moor only 35 of a flock of 20,000 sheep survive.
Francis Bacon publishes the Novum Organum (beyond Aristotle's Organon) on logical thinking.
Two officers of the British East India Company attempt to claim the Table Mountain region (in present-day South Africa) for England, but fail.
Shogun Tokugawa Hidetada restores Osaka Castle. Its current appearance dates from this remodeling.
The modern violin is developed.
Witch hunts begin in Scotland.
Cornelis Drebbel, at the Thames, builds an undersea boat (history of submarines).
Juan Pablo Bonet, teacher of deaf children in the Spanish court, creates the sign alphabet.
Thirty Years' War (1618–1648) continues (principally on the territory of today's Germany).
A Short Account of the Destruction of the Indies by Bartolomé de las Casas and Origin and progress of the disturbances in the Netherlands by Johannes Gysius was re-published in the Netherlands.
William Brouncker, 2nd Viscount Brouncker (d. 1684)
Robert Morison, Scottish botanist and taxonomist (d. 1683)
January 5 – Miklós Zrínyi, Croatian military commander (d. 1664)
January 9 – Anton Günther I, Count of Schwarzburg-Sondershausen (d. 1666)
January 17 – Anton Janson, Dutch type founder and printer (d. 1687)
January 31 – Prince Georg Friedrich of Waldeck, Dutch General and German Field Marshal (d. 1692)
February 1 – Gustaf Bonde, Swedish politician (d. 1667)
February 3 – Sir James Clavering, 1st Baronet, English landowner (d. 1702)
February 4 – Gustaf Bonde, Swedish statesman (d. 1667)
February 5 – Paul Barbette, Dutch physician (d. 1666)
February 13 – Girolamo Casanata, Italian cardinal (d. 1700)
February 15 – François Charpentier, French archaeologist and man of letters (d. 1702)
February 16 – Frederick William, Elector of Brandenburg (d. 1688)
February 23 – Francis Newport, 1st Earl of Bradford, English politician (d. 1708)
March 10 – Johann Heinrich Hottinger, Swiss philologist and theologian (d. 1667)
March 13 – Alexander Seton, 1st Viscount of Kingston (d. 1691)
March 29 – Edward Digges, English barrister and colonist, Colonial Governor of Virginia (d. 1674)
April 17 – Marguerite Bourgeoys, French Catholic nun, founder of the Congregation of Notre Dame (d. 1700)
April 18 – Winston Churchill (1620–1688) (d. 1688)
April 21 – Salvatore Castiglione, Italian painter (d. 1676)
April 24 – John Graunt (d. 1674)
May 3 – Bogusław Radziwiłł, Polish-Lithuanian noble (d. 1669)
May 23 – Pieter Neefs the Younger, Flemish painter (d. 1675)
May 25 – Warwick Mohun, 2nd Baron Mohun of Okehampton, Member of the English Parliament (d. 1665)
June 6 – Sir John Covert, 1st Baronet, English politician (d. 1679)
June 11 – John Moore (Lord Mayor), Member of Parliament for the City of London (d. 1702)
July 8 – Zhang Huangyan (张煌言), Chinese writer，poet and military official of Ming dynasty(d. 1664)
Nikolaes Heinsius the Elder, Dutch scholar (d. 1681)
Camillo Massimo, Cardinal and patron of the arts (d. 1677)
July 21 – Jean Picard, French astronomer and priest (d. 1704)
July 31 – Juan Ignacio de la Carrera Yturgoyen, Chilean politician (d. 1682)
August 6 – William Hiseland (d. 1732)
August 22 – Alexander Rigby (died 1694), English politician (d. 1694)
August 24 – Thomas Stucley (MP), English politician (d. 1663)
August 26 – Ernst Bogislaw von Croÿ (d. 1684)
September 4 – Ernest Gottlieb, Prince of Anhalt-Plötzkau (d. 1654)
September 6 – Isabella Leonarda, Italian composer (d. 1704)
September 18 – Albert II, Margrave of Brandenburg-Ansbach, German prince (d. 1667)
September 29 – John Louis of Elderen (d. 1694)
October 1 – Nicolaes Pieterszoon Berchem, Dutch Golden Age painter of pastoral landscapes (d. 1683)
October 4 – François-Henri Salomon de Virelade, French lawyer (d. 1670)
October 15 – William Borlase (died 1665), English politician (d. 1665)
October 16 – Pierre Paul Puget, French painter (d. 1694)
October 20 – Aelbert Cuyp, Dutch painter (d. 1691)
October 27 – Philip Louis, Duke of Schleswig-Holstein-Sonderburg-Wiesenburg (d. 1689)
October 31 – John Evelyn, English diarist and writer (d. 1706)
Ninon de l'Enclos, French author (d. 1705)
Theodoor Boeyermans, Flemish Baroque painter (d. 1678)
November 20 – Peregrine White, first English child born at Plymouth Colony (d. 1704)
Henri Charles de La Trémoille, son of Henry de La Trémoille (d. 1672)
Maurice of the Palatinate, Fourth son of Frederick V, Elector Palatine (d. 1652)
December 18 – Heinrich Roth, missionary and pioneering Sanskrit scholar (d. 1668)
December 23 – Johann Jakob Wepfer, Swiss pathologist (d. 1695)
undated – Ecaterina Cercheza, Princess consort of Moldavia (d. 1666)
January 23 – John Croke, English politician and judge (b. 1553)
January 26 – Amar Singh I (b. 1559)
January 28 – Archduchess Eleanor of Austria, Archduchess of Austria (b. 1582)
February 15 – James Archer, Irish member of the Society of Jesus; played a controversial role in the Nine Years' War (b. 1550)
Al-Mansur al-Qasim, Imam of Yemen (b. 1559)
Roemer Visscher, Dutch writer (b. 1547)
February 23 – Nicholas Fuller, English politician (b. 1543)
March 1 – Thomas Campion, English poet and composer (b. 1567)
March 5 – Giovanni Francesco Sagredo, Italian mathematician (b. 1571)
March 17 – St. John Sarkander, Moravian priest (injuries caused by torturing) (b. 1576)
March 25 – Johannes Nucius, German composer (b. c. 1556)
April 8 – Angelo Rocca, Italian humanist (b. 1545)
April 30 – John Flower, English politician (b. 1535)
May 6 – Hayyim ben Joseph Vital, Palestinian-born Kabbalist (b. 1543)
May 16 – William Adams, English navigator and samurai (b. 1564)
May 30 – Mathias Hovius, Roman Catholic archbishop (b. 1542)
June 17 – Mikołaj Zebrzydowski (b. 1553)
July 13 – William Louis, Count of Nassau-Dillenburg (b. 1560)
August 2 – Carolus Luython, Belgian composer (b. 1557)
August 14 – Katherine Hastings, Countess of Huntingdon, wife of Henry Hastings, 3rd Earl of Huntingdon (b. 1540)
August 18 – Wanli Emperor, of China (b. 1563)
September 13 – Wolfgang Hirschbach, German legal scholar (b. 1570)
September 26 – Taichang Emperor, fourteenth emperor of the Ming dynasty of China (b. 1582)
October 7 – Stanisław Żółkiewski, Polish nobleman of the Lubicz coat of arms (b. 1547)
November 6 – Philip III, Margrave of Baden-Rodemachern (1588–1620) (b. 1567)
November 7 – Robert Hesketh, English politician (b. 1560)
November 9 – Louise de Coligny, daughter of Gaspard II de Coligny; fourth and last spouse of William the Silent (b. 1555)
November 11 – Isaac and Josias Habrecht (b. 1544)
November 27 – Francis, Duke of Pomerania-Stettin, Bishop of Cammin (b. 1577)
December 3 – Janusz Radziwiłł (b. 1579)
December 21 – George Fleetwood, English politician (b. 1564)
date unknown – Rose of Turaida, famous Latvian murder victim (b. 1601)
approximate date – Brianda Pereira, Azorean Portuguese heroine (b. 1550)
1620 (MDCXX) was a leap year starting on Wednesday (dominical letter ED) of the Gregorian calendar and a leap year starting on Saturday (dominical letter BA) of the Julian calendar, the 1620th year of the Common Era (CE) and Anno Domini (AD) designations, the 620th year of the 2nd millennium, the 20th year of the 17th century, and the 1st year of the 1620s decade. As of the start of 1620, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.