The phrase "stolen land" refers to the situation where someone's land or territory has been taken from them by force or unfair means, denying them their rights and ownership. Full definition
The real reason people don't want to recognize it though, is that they don't want to be reminded that they are still living on stolen land. (rachelheldevans.com)
There are several scenes in Hostiles in which white soldiers elaborately apologize to Native Americans for stealing their land, and, while poignant, they feel like a sop to contemporary priorities. (slantmagazine.com)