Fermi National Accelerator Laboratory (Fermilab), located in Batavia near Chicago, Illinois, is a US Department of Energy national laboratory specializing in high-energy particle physics. As of January 1, 2007, Fermilab is operated by the Fermi Research Alliance, a joint venture of the University of Chicago and the Universities Research Association (URA). Fermilab is a part of the Illinois Technology and Research Corridor.

Fermilab's Tevatron is a landmark particle accelerator; at 3.9 miles (6.3 km) in circumference, it is the world's second largest energy particle accelerator (CERN's Large Hadron Collider is 27 km in circumference). In 1995, both the CDF and DØ (detectors which utilize the Tevatron) experiments announced the discovery of the top quark. In addition to high energy collider physics, Fermilab is also host to a number of smaller fixed-target and neutrino experiments, such as MiniBooNE (Mini Booster Neutrino Experiment), SciBooNE (SciBar Booster Neutrino Experiment) and MINOS (Main Injector Neutrino Oscillation Search). The MiniBooNE detector is a 40-foot (12 m) diameter sphere which contains 800 tons of mineral oil lined with 1520 individual phototube detectors. An estimated 1 million neutrino events are recorded each year. SciBooNE is the newest neutrino experiment at Fermilab; it sits in the same neutrino beam as MiniBooNE but has fine-grained tracking capabilities. The MINOS experiment uses Fermilab's NuMI (Neutrinos at the Main Injector) beam, which is an intense beam of neutrinos that travels 455 miles (732 km) through the Earth to the Soudan Mine in Minnesota.

In the public realm, Fermilab is host to many cultural events, not only public science lectures and symposia, but classical and contemporary music concerts, folk dancing and arts galleries, when the Homeland Security Advisory System permits.[citation needed] Currently the site is open to all visitors from dawn to dusk who present valid photo identification.