For the past 30 years practitioners of lattice QCD have been working hard to perform ab initio simulations of the strong nuclear force. However only recently has the required computer power become available to allow calculations precise enough to reliably compare to experiment providing direct confirmation of some non-perturbative aspects of QCD. I will present an overview of the US lattice QCD community's efforts to date on performing large scale QCD simulations on the current Teraflops scale machines along with our plans to prepare for the future set of leadership class Petaflops machines.