tl;dr: CMS (Compact Muon Solenoid) is one of two major detectors of the Large Hadron collider. Fermilab was intimately involved in designing CMS. Fermilab is also a "tier 1" computation center for processing LHC data (possibly restricted to CMS data?). Per this factsheet[1], there is one other "tier 1" compute farm in the US, though it isn't named in particular. I'd guess Lawrence Livermore, but I have nothing more than a hunch.
[1] https://www.fnal.gov/gridfest/pdfs/uscomputing_factsheet.pdf