NOvA is a long-baseline neutrino experiment that studies how neutrinos change as they travel from Fermilab in Illinois to a far detector at Ash River, Minnesota, 810 kilometers away. Built as a successor to MINOS, it focuses on muon neutrinos transforming into electron neutrinos and measures key properties such as mixing, mass splitting, possible CP violation, and the neutrino mass hierarchy. Its off-axis beam design narrows the energy range and reduces background, while matching liquid-scintillator detectors compare the beam before and after oscillation. After a temporary funding setback in 2008, NOvA began full operation in 2014 and also supports neutrino interaction studies and supernova alerts.