Certain classes of binary constant weight codes can be represented geometrically using linear structures in Euclidean space. The geometric treatment is concerned mostly with codes with minimum distance 2(w − 1), that is, where any two codewords coincide in at most one entry; an algebraic generalization of parts of the theory also applies to some codes without this property. The presented theorems lead to several improvements of the tables of lower bounds on A(n, d, w) maintained by E. M. Rains and N. J. A. Sloane, and the ones recently published by D. H. Smith, L. A. Hughes and S. Perkins. Some of these new codes can be proven optimal.