NSF REU (Research Experiences for Undergraduates)

An NSF Research Experiences for Undergraduates (REU) award is one of two distinct funding mechanisms — an REU Site or an REU Supplement — through which the U.S. National Science Foundation pays for undergraduates to do mentored, hands-on research. Both are governed by the same active solicitation, NSF 23-601, “Research Experiences for Undergraduates (REU) — Sites and Supplements.”

REU is a distinct line item in a grants office’s NSF portfolio: unlike a graduate fellowship (NSF GRFP) or a postdoctoral fellowship, it is never applied for or held by the student individually — it is always held by an institution (a Site) or attached to an existing PI-held award (a Supplement).

The two REU mechanisms: Sites vs. Supplements

NSF’s own solicitation language draws the line cleanly between the two:

• REU Sites are “based on independent proposals to initiate and conduct projects that engage a number of students in research.” A Site is its own standalone, competitively reviewed award — typically led by a single Principal Investigator (with one additional Co-PI permitted where shared responsibility is warranted) — that recruits and hosts a cohort of undergraduates, commonly 8–10 per year, for a defined period of mentored research, most often an 8–10 week summer program. A Site may be based in a single department/discipline or organized around an interdisciplinary theme spanning several departments.
• REU Supplements are not a standalone competition at all — they add undergraduate-research funding to a project NSF is already funding. Per the solicitation, a Supplement “may be included as a component of proposals for new or renewal NSF grants or cooperative agreements or may be requested for ongoing NSF-funded research projects.” In practice this means a PI with an active or newly proposed NSF award requests additional funds — either at proposal stage or afterward, through their cognizant program officer via Research.gov — specifically to bring one or more undergraduates onto the existing project, rather than the PI (or their institution) competing for a new, separate Site award.

Both mechanisms fund the same underlying activity — authentic mentored research experience for undergraduates — but they sit at different points in the grants lifecycle: a Site is a proposal a grants office prepares and submits in its own right; a Supplement is a post- or pre-award administrative request layered onto a grant the institution already holds.

Eligibility, and how students actually apply

Student eligibility is the same under either mechanism: undergraduate participants (pursuing an associate’s or bachelor’s degree) must be U.S. citizens, U.S. nationals, or U.S. permanent residents. Beyond that baseline, NSF does not run a centralized application process — students do not apply to NSF itself. Each REU Site (and each Supplement-funded position) sets and runs its own application and selection process independently; NSF’s role is limited to funding the Site or Supplement, not selecting participants. Students typically locate opportunities through NSF’s public Directory of REU Sites or the NSF Education and Training Application (ETAP) system, then apply directly to individual Sites with materials the Site itself requires — commonly a résumé, statement of interest, transcript, and references. Most Sites run in the summer with student application windows in the January–March range, though some operate during the academic year.

Award size, duration, and program volume

Per NSF 23-601, a typical REU Site award runs roughly $100,000–$155,000 per year, most commonly for a 3-year period (up to 5 years is allowed in some cases), supporting a cohort of about 8–10 students annually. Solicitation-level program estimates put total REU activity (Sites and Supplements combined) at approximately 1,300–1,350 awards per year, comprising roughly 175 new Site awards and 1,150 new Supplement awards, drawing on total program funding NSF has estimated at around $84.8 million in a recent fiscal year — actual annual figures depend on NSF’s appropriated budget and vary by fiscal year. REU Site proposals are accepted on a fixed annual cycle: the standing deadline is the third Wednesday in August each year (5:00 p.m. local time of the submitting organization), recurring annually under the current solicitation.

Why REU matters for grants administrators specifically

For a sponsored-programs or research-administration office, REU is worth tracking as its own category distinct from the graduate- and postdoctoral-stage mechanisms already covered elsewhere on this site, for a few concrete reasons:

• It’s a proposal type in its own right, not just a budget line. An REU Site is prepared, submitted, and post-award-administered like any other NSF grant — project description, budget, biosketches (via SciENcv, see CASRAI’s NSF Biosketch (SciENcv) entry), current-and-pending disclosures, and its own reporting cycle — and it sits alongside, not underneath, an institution’s research-grant portfolio.
• The Supplement path has different mechanics from a fresh proposal. Because a Supplement is requested against an existing award rather than competed independently, the administrative path runs through the cognizant program officer and Research.gov rather than a full proposal submission — grants staff supporting a PI who wants to add undergraduates to a funded project need to know this is a request, not a new competition, and that eligibility depends on the PI already holding (or concurrently proposing) the underlying NSF award.
• It is genuinely distinct from NSF’s graduate and postdoctoral funding. REU funds undergraduates specifically, for a defined short-term mentored experience, held institutionally or attached to a PI’s grant — not by the student. That is a different structure from NSF’s individually-held, portable postdoctoral mechanisms (Postdoctoral Research Fellowships in Biology, MSPRF, and others described in CASRAI’s postdoctoral fellowship entry) or NIH’s individually-held predoctoral F31. A grants office should not file REU administration under the same process as an individual fellowship award — the funding recipient, the proposal mechanics, and the reporting obligations are all different.
• It’s a recurring, predictable line for institutions that run Sites. Because the deadline is fixed annually (third Wednesday in August) and awards commonly run 3 years, an REU Site is a multi-year administrative commitment — cohort recruitment, stipend/housing logistics, and annual reporting — that a grants office plans around much like any other multi-year cooperative award, distinct from the one-time administrative touch of processing a single Supplement request.

For the broader landscape of how REU sits within NSF’s funding structure — proposal types, review process, and award administration generally — see CASRAI’s NSF Grants: An Overview guide.

References

• NSF 23-601, “Research Experiences for Undergraduates (REU) — Sites and Supplements” (nsf.gov/funding/opportunities/reu-research-experiences-undergraduates/nsf23-601/solicitation)
• NSF, “Research Experiences for Undergraduates” program overview (nsf.gov/funding/initiatives/reu)
• NSF, “NSF REU: Information for Students” (nsf.gov/funding/initiatives/reu/students)
• NSF, “NSF REU: Information for Faculty” (nsf.gov/funding/initiatives/reu/faculty)