The following is a timeline of the history of the city of Denver, Colorado, United States, from its founding in 1858 to the present.
1800s
1855 to 1879
By 1855, the area surrounding present-day Denver remained sparsely populated, though American trappers, traders, military surveyors, and overland travelers regularly passed through the South Platte River valley. Small numbers of American prospectors and settlers had begun entering the region in advance of the later gold rush, but no permanent American town had yet been established in the immediate area. https://www.rivertrailonline.org/historic-timeline
1858 September 24: A group of squatters draw up an agreement to found the St. Charles Town Association in what is now downtown Denver. November 1: The settlement of Auraria, Kansas Territory founded in the low ground near the confluence of the Platte and Cherry Creek. November 22: Denver City founded east of Cherry Creek as a rival to Auraria, displacing the St. Charles Association. 1859 The first burial ground, the Mount Prospect Cemetery (later called the Old Denver City Cemetery) was established. John C. Moore becomes mayor. April 23: Rocky Mountain News begins publication. May 7: First stagecoaches of the Leavenworth and Pike's Peak Stage Company arrive in Denver. October 3: The first school, a private institution founded by O.J. Goldrick, opens for classes in Auraria on 12th Street between Market and Larimer Streets. 1860 Population of the City: 4,749 Construction of the first canal called, the "Big Ditch", to deliver water to the city begun by the Capitol Hydraulic Company. January – Denver Police Department established by Mayor Moore, replacing Denver Marshals. April 6: Moonlight ceremony on Larimer Street bridge over Cherry Creek unites Auraria with Denver City. May 18: Barney Ford, who later became an important civil rights activist, arrives in Denver for the first time. July – Clark, Gruber & Co. a privately owned gold brokerage and mint, produces the first coins in Colorado. September – "People's Government" formed in the Apollo Hall Saloon in Larimer Square. October 6: James Gordon executed by hanging for the drunken murder of German immigrant Jacob Gantz by order of the "People's Court" and Alexander Cameron Hunt presiding as judge. 1861 Denver City becomes part of Colorado Territory. November 19: "People's Government" of Denver replaced by the territorial government. 1863 Telegraph begins operating. April 19: Fire destroys much of Downtown and results in laws requiring new buildings to be made of brick. 1864 St. Mary's Academy founded by the Sisters of Loretto. University of Denver founded as the Colorado Seminary by the Methodist Episcopal Church. May 19: Cherry Creek floods destroying city records. 1867 Colorado Tribune newspaper begins publication. Platte Water Company finishes the "Big Ditch" to provide Denver with water, terminating in Smith Lake in what is today Washington Park. December – Legislature of Colorado Territory votes to relocate to Denver City from Golden City. 1868 Schools in Denver segregated due to the demands of parents, a separate school for black students being founded at 16th and Market Streets. May 18: Public holiday declared to celebrate the start of construction on the Denver Pacific Railroad to connect with the Union Pacific Railroad in Cheyenne, Wyoming. 1870 Population of the City: 4,759 June 22: Denver Pacific Railroad completed to Cheyenne, Wyoming. August 15: Kansas Pacific Railway completed near modern day Strasburg, Colorado, giving Denver its second railroad connection. November: Denver City Water Company formed. 1871 December 17: Denver Horse Railroad the first rail transit service begins operating, changing its name in the next year to the Denver City Railway Co. 1873 – Palace Theater, a gambling and entertainment establishment, opened by Ed Chase. 1875 – East High School opens as part of the Arapahoe School. 1876 Riverside Cemetery established. August 1: Denver becomes part of new State of Colorado. 1878 Central Presbyterian Church completed. Historic Evans Memorial Chapel built by with funding from former territorial governor John Evans. 1879 Typhoid fever outbreak sickens more than 600 residents and kills at least 40. First of six significant outbreaks that occur through 1896 due to contaminated water. February 24: first telephone exchange in city opens, one of the first 25 in the world. July 11: State Historical and Natural History Society of Colorado, later History Colorado headquartered in Denver. September 1: Delivery of mail to addresses starts in Denver with six mail carriers.
1880 to 1899 1880 Population of the City: 35,62950th most populous US city. First time in 100 most populous cities in the US. Denver Club, a private gentleman's club founded by leading wealthy residents. 1881 April 13: Denver Fortnightly Club, one of Denver's first women's clubs has its first meeting. June 1: Union Station opens. September 5: Opening of the Tabor Grand Opera House by a production of Maritana. 1882 High Line Canal opens to provide water to agricultural areas south of Denver. February 18: Purchase of land for City Park approved by Denver City Council. December – Colorado Scientific Society founded in Denver, not incorporated until January 1885. 1883 First St. Patrick's Day parade organized by Father Joseph P. Carrigan. Second City Hall completed. Arapahoe County Courthouse completed on 16th and Tremont Streets. It served until 1902 when Denver was separated from the county. 1884 Denver Athletic Club founded. July – Denver Press Club organized. 1885 November – Mercantile Library, a predecessor of the Public Library, opened by the Denver Chamber of Commerce. 1886 The Holden Smelter, which later became the ASARCO Globe Plant begins operating. Construction begins on the Colorado State Capitol building. Denver Union Stockyards Company moves to location on the South Platte River bounded by 46th Avenue and 52nd Avenue to the north. "Ugly law" effected, prohibiting those deemed unsightly (generally the impoverished) from public spaces. July 31: Denver Tramway operates first passenger car on 15th Street. 1887 College of the Sacred Heart (later renamed Regis University) relocates to Denver. February 28: Congress votes to establish an army base near Denver, later named Fort Logan, due to the petitioning of the citizens of the city. 1889 Construction of the Boston Building, Denver's first modern office building begins. Denver Athletic Club's historic clubhouse is built. July 30: Soapy Smith assaults and injures Rocky Mountain News editor John Arkins. The News declares a crusade to rid Denver of the bad man, which took a decade to complete. November: Permission granted to Citizens' Water Company to go into competition with the established Denver Water Company to build a system to provide water to the city. 1890 Population of the City: 106,71326th most populous US city. Mount Prospect, the Denver City Cemetery, closed to further burials. April 8: Construction of the Masonic Temple begins at 16th and Welton Streets. May 1: Elitch Gardens amusement venue opens. 1891 Central Presbyterian Church built. Oxford Hotel, Denver's oldest still existing hotel, built. May 1: Town of Colfax incorporates in what is now the Sun Valley neighborhood. 1892 The Denver Post newspaper begins publication as the Evening Post. January: The competing town of Brooklyn incorporated an area inside the town of Colfax setting up a six month fight that was ultimately won by the town of Colfax. August 12: Brown Palace Hotel opens. 1893 Denver's oldest continuously operating restaurant, the Buckhorn Exchange opens under the name "The Rio Grande Exchange". Denver government orders all bodies to be removed from the old City Cemetery. Denver Artist Club, which later became the Denver Art Museum founded. June – Silver prices fall from $1.05 per ounce to 83¢ per ounce, starting the Denver Depression. July 18: Six Denver banks fail. 19: Three more banks suspend payments. 1894 Citizens' Water Company purchases and merges with rival taking the new name, the Denver Union Water Company. February 7: South Denver annexed by the city. Colorado State Capitol building complete, Governor Davis Hanson Waite moves his office to the building. March 15: Governor Waite orders state militiamen to march on Denver City Hall to remove the Police and Fire Commissioners in what became known as the City Hall War. 1895 October 22–24 First annual Festival of Mountain and Plain. 1896 – Denver Zoo founded because of the gift of an orphan bear to Mayor Thomas S. McMurray. 1898 Denver Public Library established. February 1: Around 10,000 people attempt to attend the funeral of the Congregationalist minister and social reformer Myron W. Reed. 1899 Washington Park began development, the first phase lasting to 1908. National Jewish Health opens. Spring: Construction of Cheesman Dam begins.
1900s
1900 to 1919 1900 Population of the City: 133,85925th most populous US city. May 3: Spring flood overtops the still under construction Cheesman Dam, flooding low lying areas of Littleton at about 1:00 in the afternoon and sweeping away all but the foundations of the dam. December 6: Denver Museum of Nature and Science incorporated as the Colorado Natural History Museum. 1902 Voters approve Article XX of the Colorado State Constitution, popularly known as the Rush Amendment, granting home rule for the Government of Denver. Grant–Humphreys Mansion built. June 21: USS Denver (CL-16), named in honor of the city, launched in Philadelphia. 1903 Denver Juvenile Court established. July – What will become the east wing of the Denver Museum of Nature and Science Completed in City Park. 1904 May – Robert W. Speer elected mayor for the first time. Judge and reformer Ben B. Lindsey later alleged there were 10,000 illegal votes cast in the election. 1905 May 9: Water reaches the spillway of the Cheesman Dam. Constructed by the Denver Union Water Company, on the South Platte River, it is the city's first mountain water reservoir and the tallest in the world at the time of completion. Mayor Speer starts tree planting program. 1906 Municipal code adopted. U.S. Denver Mint begins minting coins. January 29: First National Western Stock Show begins. 1908 Municipal Auditorium opens. A year after the death of Walter Cheesman construction is complete on his mansion, which will later become the Colorado Governor's Mansion. The dome of the state capitol gilded with gold for the first time by state mining industry. July 1: Colorado Natural History Museum opens to public, later renamed Denver Museum of Nature and Science. 7–10: 1908 Democratic National Convention held in Denver Auditorium Arena. 23: Denver and Interurban Railroad from Denver to Boulder begins operation. 1910 Population of the City & County: 213,38127th most populous US city. Construction of the Cheesman memorial in what would become Cheesman Park begins. Denver Gas & Electric Building, a building studded with then modern electric bulbs, completed. Dumb Friends League established. August 11: Children's Hospital Colorado opens. 1911 Daniels & Fisher Tower completed. The city enacts gun control law making the carrying of concealed guns a felony offence. Charles Gates Sr. purchases Colorado Tire and Leather Company, the business that will eventually become the Gates Corporation. July 17: Mountain States Telephone & Telegraph Company formed in merger of Colorado Telephone, Tri-State Telephone, and Rocky Mountain Bell Telephone. 1912 January: E.W. Merritt leads fundraising campaign to raise the money to save land in what will become Genesee Park from being logged. May 21: Voters enact a property tax to acquire lands and build amenities for the Denver Mountain Parks.