The St. Joseph's Mission Cemetery is located near Williams Lake, British Columbia.  The site was a Roman Catholic mission established in 1867 & was operated by the Missionary Oblates of Mary Immaculate. It is primarily known for the notorious St. Joseph's Indian Residential School located on the property, a part of the Canadian Indian residential school system that operated on the Mission from 1891 to 1981.

While different from the Home Children movement across Commonwealth nations, the Canadian Indian Residential School system particularly at this location was designed to convert the local Shuswap peoples to Christianity (Catholicism) & to reorganize their village life into a hierarchical administration imposed by the Catholic church.  On the outside, there was nothing to note.  However during the school's history, many student deaths were recorded which resulted in multiple public inquiries into conditions at the school, as early as 1902.  During that year, nine boys ran away from the school, one of them dying of exposure. In 1920, nine boys ate poisonous water hemlock in what parents believed to be a response to discipline at the school. One of these boys died. The school closed in 1981. In the 1980s and 1990s two former staff members pled guilty to charges of sexually abusing students in the 1950s and 1960s. In 1998, a former principal apologized to a former student and school employee who had charged him with a series of sex offences.  Following the school's closure, several school staff were imprisoned for sexual abuse. In June 2008 a public apology regarding the mistreatment of students at this site was made by Prime Minister Stephen Harper.  A school reunion in 2013 resulted in the creation of Orange Shirt Day, which later became a Canadian statutory holiday.

In addition to the mistreatment, the Canadian Indian Residential School system recorded b/w 3,200 & 6,000 student deaths, mostly from tuberculosis.  The exact number is unknown due to incomplete records.  Bodies, unmarked graves, & potential burial sites have been identified across the country since the 1970s.  Ground disturbances on radar at the nearby Kamloops Indian Residential School in May 2021 revealed the presence of 215 unmarked children's graves.

In June 2021, a search was announced of the site of St. Joseph's Mission Residential School near Williams Lake, led by Williams Lake First Nation, using ground-penetrating radar, and focusing on 0.15 square kilometres of the 4.5 square kilometre site. Work began in late August 2021. On January 25, 2022, the chief of Williams Lake First Nations announced that 93 potential burial sites were discovered.

The investigation continued, and on January 24, 2023, the Nation announced that it had come to the conclusion that at least 28 children had died while students of the school, as opposed to the 16 reported by the National Centre for Truth and Reconciliation. The announcement also identified 66 more potential burial sites, for a total of 159, identified using GPR and aerial and terrestrial LiDAR. The Nation also announced that it was working with the B.C. Coroner's Service and attorney general to create a memorandum of understanding that would allow them to proceed with further work to confirm the potential gravesites, using small probes and DNA testing.

When the mission first opened, it contained the only cemetery in the area until Williams Lake was granted official town status in 1920 and began its own cemetery. Today, the grounds of the cemetery and the foundations of the former school building are mostly untended, and are marked as a historic site of the province of British Columbia.  

More info here: https://en.wikipedia.org/wiki/Saint_Joseph%27s_Mission_(Williams_Lake)

https://collections.irshdc.ubc.ca/index.php/Detail/entities/42

https://en.wikipedia.org/wiki/Canadian_Indian_residential_school_gravesites

https://www.jstor.org/stable/483086