Crystal structure determinations of the Pb(ii) complexes of the isomeric 2,3-, 2,4-, and 2,5-pyridinedicarboxylates (pdca) of composition Pb(2,3-pdca), Pb(2,4-pdca)·H₂O, and Pb(2,5-pdcaH)₂·2H₂O show that, as in the known 2,6-pyridine-dicarboxylate (dipicolinate, commonly designated ‘dipic’ but here, for the sake of consistency, as 2,6-pdca) complexes Pb(2,6-pdca)(2,6-pdcaH₂)·3H₂O and Pb(2,6-pdca), stacking of the aromatic moieties is a prominent feature of the lattices. Structural evidence can also be discerned for the possible influence of other forces such as Pb···Pb bonding and lone-pair repulsions, but the lattices differ markedly in these regards.