The Central Apennine Mountains run from the Tuscana Border through the Regions of Tuscany, Umbria, Abruzzo, Molise, and parts of Lazio. The area is well developed with regional hiking routes and there is a plan to connect many of these routes into a national route. Many of the areas are designated as National Parks and provide a remote escape for those who enjoy getting away from the crowds and immerse themselves in nature.
A natural border exists between the Northern Apennines and the Central Apennines: a klippen zone, or band of isolated Liguride rocks, follows the Val Marecchia ("Valley of the Marecchia River") to the Marches-Tuscany border and passes through the Monti Rognosi and Arezzo in Tuscany. If extended the line would touch the northern tip of Corsica, but it is only relevant on the east slopes of the Apennines, where it is located just south of the border between Marches and Emilia-Romagna. The west border of the Umbrian-Marchean Apennines (or "Umbro-Marchean") runs through Cagli. They extend south to the Tronto River, the south border of the ONA. In the northeast of the range, the Republic of San Marino is located on the slopes of Monte Titano. The highest peak, Monte Vettore, at , is part of the Monti Sibillini, incorporated into Parco Nazionale dei Monti Sibillini. Further inland is Parco Sasso Simone e Simoncello and further south Parco naturale regionale Gola della Rossa di Frasassi, in which are the Gola della Rossa ("Canyon of the Red") and Frasassi Caves. The Italian Park Service calls it the "green heart" of Italy. The region is heavily forested, such as the Riserva Naturale Statale Gola del Furlo, where Furlo Pass on the Via Flaminia is located. Both the Etruscans and the Romans constructed tunnels here.
The Tiber River at Rome flows from northeast to southwest, projecting into the Tyrrhenian Sea at right angles to the shore. The upper Tiber, however, flows from northwest to southeast, gradually turning through one right angle clockwise. In the north Val Tevere ("Valley of the Tiber") is a deep valley separating the Umbrian Apennines on the left bank from a lesser range, the Tuscan Anti- or Sub-Apennines on its right. They and some of Val Tevere are part of Tuscany, which formerly was enclosed by the Arno River, the Tiber River and the coast, but has lost ground around the Tiber to Lazio and Umbria. Lazio extends a little way up the Tiber. Val Tevere, however, is mainly in Umbria. In the Apennines also and on the west coast is Marches. The Val Tevere is marked on the map by Highway A1, the Autostrada del Sole, which enters it in the vicinity of Monte Rotondo north of Rome and follows the course of the river to the point where the latter flows from Lago di Cabara in the vicinity of Baschi and then goes up the valley of the Fiume Paglia.
North of the lake the course of the Fiume Tevere is marked by Highway E45 almost to where the Tevere begins at Falera on the slopes of Monte Fumaiolo. That location is in Emilia-Romagna. For that entire distance the eastern slopes of the Apennines are in Marches.Ancient Umbria included most of Marches (which did not then exist) except for the Adriatic coast and did not include Val Tevere, which belonged to Etruria all the way to the Tyrrhenian Sea. Names of regions and the geographical features associated with them; for example, "the Tuscan Hills" depend on the historical period. South of Monte Fumaiolo the Tevere enters Tuscany.
It crosses the Umbrian border in the vicinity of San Giustino and remains in it, becoming part of the border between Umbria and Lazio in the south, entering Lazio unequivocally in the vicinity of Castello delle Formiche. Over the centuries these borders have varied, mainly at the expense of Tuscany. Consequently there has been considerable imprecision in locating the Umbrian Apennines, and therefore the highest peak in them. The major difficulty is discriminating the Umbrian of the Northern Apennines from the Umbrian-Marchean of the Central Apennines. The mountains of Umbria and Marches are so wide and so tangled, rather than parallel, that the borders are difficult to place and vary according to author. Many do not make the distinction, but one is still recognized, by the Italian park service.
In general, the Umbrian Apennines are located mainly in Umbria, while the great mass of mountains in Marches are considered Central Apennine. Merriam-Webster's Geographical Dictionary defines the Umbrian Apennines to extend from the "sources of the Tiber" to Scheggia Pass, bounded on the east by the border between Umbria and Marches, which runs along the divide. Similarly the Alto Tevere begins near the border between Tuscany and Emilia-Romagna. The pass is the point where the Roman Via Flaminia crosses the divide. Starting from Rimini on the Adriatic coast the old road follows the coast south to Fano, then turns inland and goes up the Fiume Metauro to Ponti di Traiano, then up the Fiume Candigliano to Acqualagna, and by the Fiume Burano to Cagli (ancient Cales). Here the Via Flaminia turns south, approximated today by highway SP3, which climbing the flanks of Monte Fiume arrives at last at the pass. This is the southernmost limit of the Umbrian Apennines, according to the dictionary. The pass goes down to Gualdo Tadino (Tadinium).
Gubbio is east of the Val Tevere. The region specified by the dictionary includes Monte Nerone, which is actually in Marches. South of the pass the same chain is in Umbria and includes a number of parklands considered by the Italians to be in the northern Apennines. The LOTO Project (Landscape Opportunities for Territorial Organization), a recent pilot study for regional landscape planning undertaken by the European Institute of Cultural Routes, an agency of the European Union, simply calls it "the Apennine Ridge" of "the Umbria Region," which it locates in "the central and northern mountains of the Apennines." The western part of this range is considered by some to be the Umbrian Apennines; it includes Parco del Monte Cucco, , which includes the pass, the road and the Umbrian side of the ridge south to Fossato di Vico. Further south are Parco del Monte Subasio around Assisi and Parco di Colfiorito on the border with Marches.
The Abruzzi Apennines, located in Abruzzo, Molise (formerly part of Abruzzo) and southeastern Lazio, contain the highest peaks and most rugged terrain of the Apennines. They are known in history as the territory of the Italic peoples first defeated by the city of Rome. Coincidentally they exist in three parallel folds or chains surviving from the orogeny. These extend in a northwest-southeast direction from the River Tronto to the River Sangro, which drain into the Adriatic. The coastal hills of the east extend between San Benedetto del Tronto in the north and Torino di Sangro in the south.
The eastern chain consists mainly of the southern part of the Monti Sibillini, the Monti della Laga, the Gran Sasso d'Italia Massif and the Majella Massif. Among them are two national parks: Gran Sasso e Monti della Laga National Park and Majella National Park; and the Regional Park of the Monti Simbruini. Gran Sasso contains Corno Grande, the highest peak of the Apennines. Other features between the western and central ranges are the plain of Rieti, the valley of the Salto, and the Lago Fucino; while between the central and eastern ranges are the valleys of Aquila and Sulmona.
The chief rivers on the west are the Nera, with its tributaries the Velino and Salto, and the Aniene, both of which fall into the Tiber. On the east there is at first a succession of small rivers which flow into the Adriatic, from which the highest points of the chain are some 20 km distant, such as the Potenza, Chienti, Tenna, Tronto, Tordino, Vomano and others. The Pescara, which receives the Aterno from the north-west and the Gizio from the south-east, is more important; and so is the Sangro.
The central Apennines are crossed by the railway from Rome to Pescara via Avezzano and Sulmona: the railway from Orte to Terni (and thence to Foligno) follows the Nera valley; while from Terni a line ascends to the plain of Rieti, and thence crosses the central chain to Aquila, whence it follows the valley of the Aterno to Sulmona. In ancient times the Via Salaria, Via Caecilia and Via Valeria-Claudia all ran from Rome to the Adriatic coast. The volcanic mountains of the province of Rome are separated from the Apennines by the Tiber valley, and the Monti Lepini, part of the Volscian chain, by the valleys of the Sacco and Liri.