The NIST Center for Neutron Research (NCNR) is a research reactor at the National Institute of Standards and Technology, in Gaithersburg, Maryland. Access to the neutron instrumentation is open to any interested user, dependent on approval of an experiment proposal in a peer-reviewed system.

The neutron source is a light-water fission reactor, operated with the coolant/moderator near room temperature. Instruments with beam ports directly attached to the primary source thus receive neutrons with a Neutron temperature also near room temperature, so-called "thermal neutrons". Longer-wavelength "cold" neutrons are provided by a secondary source, consisting of a thermalizing bath of liquid Hydrogen at 10 Kelvin. From this source, 7 guide tubes (soon to be expanded to 12) carry the cold neutrons to the receiving instruments. One guide tube is further moderated to provide Ultracold neutrons to a station where fundamental physics measurements of neutron properties are carried out.

1. High Resolution Powder Diffractometer
2. Neutron Imaging Facility
3. Filter Analyzer Neutron Spectrometer
4. Triple-axis spectrometers
5. Residual Stress Diffractometer
6. Multi Axis Crystal Spectrometer (MACS)
7. Ultra Small-Angle Neutron Scattering

1. Reflectometers
   1. Horizontal geometry: for liquid and floating-layer studies
   2. Vertical geometry: for large-angle reflection/diffraction studies (2)
2. Small-Angle Neutron Scattering instruments (2)
3. Backscattering spectrometer
4. Disk-chopper time-of-flight spectrometer
5. Spin-polarized triple-axis spectrometer
6. Spin-echo spectrometer
7. Fundamental Neutron Physics
   1. Neutron lifetime (about 15 minutes)
   2. Neutron dipole moment
8. Prompt-gamma neutron activation analysis

In 2010, a project to expand the cold-neutron guide hall began. Five new guides will feed into the new section.