The following events occurred in July 1903:

• The first Tour de France bicycle race, sponsored by the French newspaper L'Auto in an effort to boost sales, is launched from the Café au Réveil-Matin in Paris.^[1]
• The metre gauge section of the Rhaetian Railway (RhB) in Switzerland opens, passing through the 1,370-metre-high (4,490 ft) Albula Tunnel in the Alps.^[2]
• The 1903 Wimbledon Championships draws to a close, with Laurence Doherty emerging as Men's Singles champion and Dorothea Douglass as Ladies' Singles champion.^[3]
• Raymond, Alberta, is incorporated as a town in Canada's North-West Territories.^[4]
• Born: Amy Johnson, English aviator, in Hull (died 1941)

• The 1903 Gordon Bennett Cup motor race is held at the Athy Circuit in Ireland and is won by Camille Jenatzy of Belgium.^[5]
• Under the Cuban–American Treaty of Relations, signed in May 1903, a second lease on Guantánamo Bay is signed by the United States and Cuba, as a result of which the U.S. will send a payment to the Cuban government each year in return for permission to use the land as a coaling and naval station.^[6]
• Born: Alec Douglas-Home, British politician, Prime Minister of the United Kingdom 1963–64, in London (died 1995); King Olav V of Norway, at Sandringham, UK (died 1991)^[7]
• Died: Ed Delahanty, American Major League Baseball left fielder and infielder, fall into Niagara River (born 1867)^[8]

• On the Osage Tribe Reservation in Oklahoma Territory, Deputy U.S. Marshal John B. Jones of the United States Marshals Service is shot and killed by a drunk man he is trying to arrest at an Independence Day celebration.^[9]
• Patrolman Louis Nelson Massey of the Evansville, Indiana Police Department is shot and mortally wounded by a man he is questioning for leaving a saloon without paying for a beer. Massey, who shoots and kills the suspect, will die of his injuries the following day.^[10]
• Born: Ace Bailey, Canadian ice hockey player, in Bracebridge, Ontario (died 1992)
• Died: Harriet Lane, 73, First Lady of the United States during the presidency of her uncle, James Buchanan

• Inaugural World Light Heavyweight Boxing Champion Jack Root loses his title, by a technical knockout, to George Gardiner at Fort Erie, Ontario, Canada, less than three months after winning it.^[11]

• Born: Hugo Theorell, Swedish scientist and Nobel laureate, in Linköping (died 1982)^[12]

• At 11:30 p.m., City Marshal John E. Cross of the Geary, Oklahoma Police Department is shot and killed while investigating three suspicious men camping on the edge of town. His body will be discovered at 5:00 a.m. the following day. The three suspects will subsequently be discovered to be members of the Martin Gang.^[13]

• French writer Jacques d'Adelswärd-Fersen is arrested on suspicion of indecent behaviour with minors and offending the public decency; he is incarcerated at La Santé Prison.^[14]
• Pennsylvania State Constable Harry Foster "Darby" Bierer of Westmoreland County, Pennsylvania is shot and killed by a man he is trying to arrest for dynamiting a mine building in Luxor, Pennsylvania. After the suspect is arrested, he confesses to 18 murders, including the August 12, 1902, killings of Patrolmen Timothy T. Devine and Charles Pennell of the Chicago Police Department. The suspect will be hanged on February 11, 1904.^[15][16][17]

• Born: O. E. Hasse, German film actor and director, in Obersitzko (died 1978)

• Born: Kenneth Clark, English art historian and broadcaster, in London (died 1983)

• Born: Adalberto Libera, Italian Modernist architect, in Trentino (died 1963)

• Died: James McNeill Whistler, 69, US painter

• US paddle steamer North Pacific loses its course in foggy conditions, strikes a rock off Marrowstone Island, Washington state, and sinks.

• The inaugural Tour de France is won by pre-race favourite, France's Maurice Garin.^[18]
• King Edward VII of the United Kingdom makes his first visit to Ireland since becoming king in 1901.^[19]
• At the county jail in Basin, Wyoming, a lynch mob of about 50 men shoots and kills Deputy Sheriff C. E. Pierce of the Big Horn County, Wyoming Sheriff's Office, who is guarding two murder suspects. The mob then breaks down the jail's doors with telephone poles and shoots and kills the two prisoners.^[20]

• Died: Pope Leo XIII, 93, Italian prelate (born Vincenzo Gioacchino Raffaele Luigi Pecci)

• The first tropical cyclone of the Atlantic hurricane season develops northeast of the Samaná Peninsula of Dominican Republic.

• The first Ford Model A automobile is sold to Chicago dentist Ernest Pfennig.^[21]
• Officer Walter W. Stansbury of the Beaumont, Texas Police Department is shot and killed by a domestic disturbance suspect who had fired at another officer. The suspect is later shot and killed by a crowd of people.^[22]

• In the by-election at Barnard Castle in the UK, brought about by the death of sitting Liberal MP, Sir Joseph Pease, Arthur Henderson takes the seat for Labour, becoming the first Labour candidate to win against both Liberal and Conservative opposition, and only the fifth Labour MP in the House of Commons.^[23]
• Chief of Police James King of the Stonega, Virginia Police Department is shot and killed while serving an arrest warrant on a moonshiner on Black Mountain. Another officer shoots and kills the suspect.^[24]

• The weekly magazine Truth is launched in Perth, Western Australia, under the editorship of John Norton.^[25][26]

• Argentina's soccer champions, Alumni Athletic Club, lose their first match in four years, and the only one of the season, to Belgrano AC.^[27]
• Deputy Constable James Casey of the Calaveras County, California Constable's Office is shot and killed by a man under arrest for public intoxication.^[28]

• Construction work begins on the Baghdad Railway in present-day Türkiye.^[29]
• Glasgow St Enoch rail accident: A Glasgow and South Western Railway train collides with buffer stops at St Enoch railway station, resulting in 17 deaths.^[30]
• Officer William Leopold Cotter of the California Department of Corrections and Rehabilitation is stabbed to death during the escape of 13 prisoners from the Folsom Penitentiary. Several other prison staff members are seriously wounded, and two members of the state militia will be shot and killed during the manhunt for the prisoners.^[31]
• Born: Michail Stasinopoulos, Greek politician, President 1974–75, in Kalamata (died 2002)
• Died: Mathridom of sultan attahiru of mbormie

@mbormi funakaye bajoga Gombe state 3

• Idaho Springs miners' strike of 1903: Philip Fire, a striking union miner, dies in an attempt to dynamite the transformer house at the "Sun and Moon" mine.^[32]

• An explosion at a United States Cartridge Company magazine in Tewksbury, Massachusetts, United States, kills 22 employees and local residents; a further 70 people are injured.^[33]

• The 2nd Congress of the Russian Social Democratic Labour Party opens in Brussels, chaired by Lenin.^[34]

• Papal conclave, 1903: The Papal conclave brought about by the death of Pope Leo XIII begins at the Sistine Chapel, Apostolic Palace, in Rome, Italy.