  Nuclear reactors are uniquely powerful, abundant, and flavor-pure sources of
antineutrinos that continue to play a vital role in the US neutrino physics
program. The US reactor antineutrino physics community is a diverse interest
group encompassing many detection technologies and many particle physics
topics, including Standard Model and short-baseline oscillations, BSM physics
searches, and reactor flux and spectrum modeling. The community's aims offer
strong complimentary with numerous aspects of the wider US neutrino program and
have direct relevance to most of the topical sub-groups composing the Snowmass
2021 Neutrino Frontier. Reactor neutrino experiments also have a direct
societal impact and have become a strong workforce and technology development
pipeline for DOE National Laboratories and universities. This white paper,
prepared as a submission to the Snowmass 2021 community organizing exercise,
will survey the state of the reactor antineutrino physics field and summarize
the ways in which current and future reactor antineutrino experiments can play
a critical role in advancing the field of particle physics in the next decade.
