Fermilab operates large clusters of computers for lattice quantum chromodynamics, as part of the national computational infrastructure for lattice QCD established by the Department of Energy. Their goal is the understanding of the strong dynamics of quarks and gluons, which is beyond the reach of the traditional perturbative methods of quantum field theory. A central goal of the groups using the computers is the accomplishment of the calculations required to extract from experiment the fundamental parameters of the Standard Model of particle physics.