Which residential schools in Canada had unmarked graves discovered in 2021 and later what methods were used to find them?
Executive summary
In 2021 community-led searches identified large numbers of possible unmarked graves at several former residential schools — notably Kamloops (Tk’emlúps te Secwépemc) with about 215/200 anomalies reported and Marieval (Cowessess) with 751 anomalies — and multiple other First Nations announced discoveries thereafter [1] [2] [3]. The primary method used was ground‑penetrating radar (GPR) and related geophysical scanning, supplemented by archival research and oral history; communities and specialists have emphasized GPR finds are “anomalies” requiring further, community‑led decisions about confirmation [4] [5] [6].
1. The headline discoveries that started the national reckoning
The wave of announcements began in late May 2021 when Tk’emlúps te Secwépemc said a ground‑penetrating radar survey had located the likely presence of roughly 215 (later clarified to about 200) potential unmarked graves at the former Kamloops Indian Residential School; weeks later Cowessess First Nation reported 751 unmarked graves at the Marieval site in Saskatchewan [1] [3]. Those two early numbers — ~200 at Kamloops and 751 at Marieval — were widely cited and triggered hundreds of other community searches across provinces [7] [3].
2. Methods used: geophysics first, archives and oral history alongside
Communities primarily used ground‑penetrating radar (GPR) and other non‑invasive geophysical tools to detect anomalies consistent with burial shafts; specialists described GPR as the central, established technique for locating unmarked graves without immediate excavation [4] [5]. Investigations were typically supplemented by archival records, church or RCMP files when available, and oral histories from survivors and families to identify likely burial areas and help interpret anomalies [8] [9].
3. What GPR actually shows — anomalies, not automatic proof of remains
Experts and reporting stressed that GPR identifies sub‑surface disturbances — changes in soil, shafts or features — that can be consistent with graves but do not by themselves confirm human remains; definitive confirmation requires further forensic steps, which many communities choose to weigh carefully for cultural reasons [8] [6]. Academic overviews note GPR is an established method for detecting unmarked graves but that interpretation requires archaeological expertise and, where desired, community‑led decisions about excavation [5] [6].
4. Scale and spread: not just two sites
After the Kamloops and Marieval announcements, dozens of First Nations began scanning former school grounds. Reporting and mapping projects tracked hundreds to thousands of potential gravesites detected as communities published preliminary GPR findings and archival identifications; some aggregations cited totals in the hundreds or low thousands as searches continued [2] [9] [10]. Individual communities used measured language — “possible,” “likely,” “anomalies” or “identified” — reflecting differing levels of archival corroboration and local decisions on further work [5].
5. Disagreement, skepticism and the politics of language
Public debate emerged quickly: many Indigenous leaders, governments and media treated the discoveries as confirmation of long‑held community testimony about deaths at schools, while some commentators and organizations challenged the leap from GPR anomalies to confirmed graves and criticized media terminology such as “mass graves” [1] [11]. Academic and fact‑checking pieces have since emphasized careful reporting: most mainstream outlets in 2021 did not use the phrase “mass graves,” and researchers warn against both minimizing community testimony and overstating forensic certainty [12] [5].
6. Cultural protocols and choices about excavation
Several sources note communities often prefer non‑invasive approaches and may avoid excavation out of cultural respect; alternatives include archival reconciliation, targeted soil sampling for environmental DNA when acceptable, and commemorative measures led by survivors and families [6] [4]. The choice to excavate, or not, is governed by each community’s priorities and by legal, ethical and resource constraints documented in reporting on the post‑2021 searches [6] [9].
7. Limitations of public reporting and what’s not in these sources
Available sources document the early, high‑profile Kamloops and Marieval findings and many subsequent GPR searches [1] [3] [4]. They do not provide a single, definitive nationwide list of every site where anomalies were later reported, nor do they report the results of forensic excavations for all sites; for many locations the reports remain preliminary or community‑managed (available sources do not mention a comprehensive national catalog of confirmed excavated graves across all sites).
Sources cited: Tk’emlúps te Secwépemc and Kamloops reporting [1] [4], Cowessess/Marieval reporting [3] [7], methods and academic context on GPR and community‑led investigations [5] [6], mapping and ongoing searches [10], and discussion of media framing and skepticism [12] [11].