The next large nuclear physics research facility being proposed to the DOE for construction is an Electron-Ion Collider (EIC). An EIC could provide unique capabilities for the study of Quantum Chromodynamics (QCD), the theory that describes how quarks and gluons build protons, neutrons and nuclei. In March 2013, NSAC ranked an EIC as “absolutely central” in its ability to contribute to world-leading science research. Two facilities, Jefferson Lab and Brookhaven National Lab in New York, are developing facility concepts.