Lager is camp (
English lair). In context this is an army camp, set up by a force of any size. This is a fairly common toponym in central and Eastern Europe (e.g. Kozachi Laheri in Kherson oblast).
Stedt is an archaic Swedish cognate of stead, stadt. The rudimentary meaning is simply place, base. Aside from compounds like instead, bedstead, homestead, farmstead, it's common in settlement names such as Hampstead, Ingolstadt etc.