The place name probably comes from the Sabine nero or nerio, which means strong, valorous. But that is not what the village says about itself: on the fountain in the square of the town hall there is an inscription — A Nerone tuum Nerola nomen habet — which traces the name to the emperor Nero, who belonged to the gens Claudia, of distant Sabine origins. On the site traces of a Roman villa seem to have been seen, which the legend duly attributed to Nero. The village, in short, has had carved into the stone of its fountain the etymology it prefers. Nerola stands at four hundred and fifty metres on the northern spurs of the Lucretili mountains, in the Roman Sabina, and it lies in the production zone of the Sabina protected-designation extra virgin olive oil.
The castrum Nerulae was founded in the second half of the tenth century by Benedetto Crescenzi, the rector of the Sabina, and the Crescenzi held it into the thirteenth century, when it passed under the direct dominion of the popes; later the fief was granted to the Orsini, who built the castle that stands now, reinforced at the end of the fourteen hundreds with mighty towers, while the borgo around it was fortified as well. In 1644 the Orsini of the Bracciano branch made over the castle and the territory of Nerola to the Barberini, together with Montelibretti; then came the Colonna di Sciarra and the Lante Della Rovere. Here was the seat of the Ospedale dei Pellegrini, the charitable institution that looked after those travelling along the via Salaria. In 1867 the castle was the scene of the campaign of the Agro Romano for the liberation of Rome: it was occupied by a contingent of Garibaldian volunteers led by Menotti Garibaldi, fighting the papal troops. In 1939 it passed to the marchese Ferrari-Frey, and today, restored, it is a hotel. The parish church of Saint George martyr was founded by the Orsini in 1482, collapsed in 1915 and was rebuilt in 1924; the former Romanesque church of Sant'Antonio abate, which had been the parish church before then, still stands with the first cemetery beside it.