Last reviewed 16 October 2026 · A three-minute read · 1780–1961
Wellton's recorded history centres on Prison Hill Road, site of the Yuma Territorial Prison, a sandstone compound above the Colorado River opposite Fort Yuma. Opened in 1876 and closed in 1909, it held thousands before becoming a schoolhouse, a Depression-era shelter, and finally a state park in 1961.
The short answer
Prison Hill Road in Wellton, Arizona, marks the Yuma Territorial Prison, opened July 1, 1876, with seven inmates including William Hall, the first prisoner. Built on a bluff above the Colorado River opposite Fort Yuma, it held 3,069 people over 33 years before closing in 1909 and reopening as a state park in 1961.
1876 to 1887
Inmates built their own cells and a prisoner uprising killed four
The Yuma Territorial Prison is now a museum, but it opened as a working prison on July 1, 1876, with its first seven inmates. One of them, William Hall, became the prison's first prisoner. Arizona's territorial legislature had approved it the year before, after two Yuma lawmen quietly rewrote a bill meant to put the prison in Phoenix instead. Ground broke on a granite bluff above the Colorado River in April that year, directly across from Fort Yuma, and the first inmates were put to work building their own cells.
Construction never really stopped. Guards added the Guard Tower and a reservoir in 1881, electric lighting in 1884, the Main Cellblock in 1895, and a solitary punishment cell known as the Dark Cell, or the Snake Den, in 1894. Inmates could be locked in it for hours or for days.
The prison's calm reputation hid a harder year. In 1887, a prisoner uprising during an escape attempt left four inmates dead and three wounded. Superintendent Thomas Gates was stabbed with a butcher's knife and badly hurt. He later took his own life to escape the pain of his injuries.
Across its 33 years, the prison held 3,069 people, including 29 women, for crimes from murder to polygamy. No one was ever executed there; death sentences were a county matter, carried out elsewhere. But 111 inmates died inside, most from tuberculosis, and the prison cemetery still holds 104 graves.
1890 to 1902
A Tombstone gunfighter and the Bandit Queen served time here
"Buckskin" Frank Leslie, a Tombstone gunfighter who had worked alongside Wyatt Earp at the Oriental Saloon, arrived in 1890. Frank Leslie had murdered his companion, Mollie Edwards, and drew a life sentence. Records differ on when he walked free. Some say Governor Benjamin J. Franklin pardoned him after six years, others say eight.
Pearl Hart arrived in 1899 after robbing the Globe-to-Florence stagecoach with Joe Boot on May 30 of that year, the last stagecoach holdup in Arizona history. Newspapers across the country ran her picture. Guards gave her one of the largest cells in the prison and let reporters photograph her there. She served only two years of a five-year term before her pardon in December 1902. Accounts differ on why, with some crediting her charm. Others say the warden had fathered a child with her, and the pardon was meant to keep it quiet.
1906 to 1909
A revolutionary was jailed here before overcrowding closed the prison
In 1906, Ricardo Flores Magón, a Mexican revolutionary who founded the Partido Liberal Mexicano against Porfirio Díaz's government, served eighteen months there for breaking U. S. Neutrality laws, and by 1909 the prison was badly overcrowded. On September 15 that year, the last prisoner left for a new state prison built in Florence, Arizona.
1910 to 1939
A burned-out high school moved into the empty cellblocks
Yuma Union High School moved into the empty cellblocks the next year, after a fire destroyed its own building. Students sat in old cells and held assemblies in the former prison hospital. Locals nicknamed the football team the Criminals. During the Great Depression, homeless families sheltered inside the abandoned cells. In 1924, the Southern Pacific Railroad tore down the western third of Prison Hill to lay new track, taking part of the old complex with it.
1939 to 1961
Locals rebuilt the ruin into Arizona's third state park
By the late 1930s, residents began raising money to save what was left. A museum went up in 1939 on the site of the old mess hall. The City of Yuma ran the site through 1960, and on January 1, 1961, it reopened as Arizona's third state park.
About eight kilometers north, Wellton's business district flooded four feet deep on February 12, 1931, when Coyote Wash overflowed its banks and killed two people.
The prison cemetery still holds 104 graves, and the cells the inmates built themselves stand open to visitors.
Read the ground you are standing on
Every person, building and event in this story opens into its own dig in the app — and Strata will dig the ground under your feet instead, wherever that is, in about a minute, with every source shown.
Sourced records, high and medium confidence. Era background is marked as such.
Deep time
The surface here sits on Holocene river alluvium, loose sand and gravel laid down by the Colorado River in the last ten thousand years.
Era background — not a record of this tile · Macrostrat
Early modern
1780
The Mission Puerto de Purísima Concepción was founded in 1780 near the Yuma Crossing, before it was destroyed in an 1781 Quechan uprising against Spanish settlers.
Jose Maria Redondo, who pushed the prison bill through the territorial legislature and later renamed Arizona City as Yuma, is buried at the Yuma Pioneer Cemetery.
In 1887 a botched escape left four prisoners dead and three wounded, and superintendent Thomas Gates was stabbed with a butcher's knife and later took his own life to escape the pain.
'Buckskin' Frank Leslie, who had worked alongside Wyatt Earp at Tombstone's Oriental Bar, arrived in 1890 after killing his companion Mollie Edwards and was pardoned years later by the governor.
Pearl Hart was locked up after robbing a stagecoach in 1899, one of the last stagecoach robberies in the Old West, and was pardoned after only two years.
After a fire destroyed its building, Yuma Union High School held classes in the old cells and used the former hospital as an assembly hall from 1910 to 1914.
In 1924 the Southern Pacific Railroad demolished the western third of Prison Hill, including parts of the old prison, to lay new tracks through the site.
A working territorial prison stood on the site, opening July 1, 1876, with seven inmates including William Hall, its first prisoner, and operating until 1909.
What happened at the Yuma Territorial Prison in 1887?
A prisoner uprising during an escape attempt left four inmates dead and three wounded. Superintendent Thomas Gates was stabbed with a butcher's knife and later took his own life to escape the pain of his injuries.
Who were the most famous inmates of Yuma Territorial Prison?
'Buckskin' Frank Leslie, a Tombstone gunfighter who had worked with Wyatt Earp, served time for murdering his companion Mollie Edwards. Pearl Hart, the 'Bandit Queen,' was jailed in 1899 after one of the last stagecoach robberies in the Old West. Ricardo Flores Magón, founder of the Partido Liberal Mexicano, served 18 months in 1906 for violating U. S. neutrality laws.
Why did the prison close?
Overcrowding forced the transfer of every remaining inmate to a new state prison in Florence, Arizona, on September 15, 1909, closing the Yuma facility for good.
What happened to the prison after it closed?
Yuma Union High School used the empty cellblocks after a fire destroyed its own building, homeless families sheltered there during the Great Depression, and in 1924 the Southern Pacific Railroad demolished a third of Prison Hill to lay track. Local fundraising led to a museum opening in 1939 and the site becoming Arizona's third state park on January 1, 1961.