Eriador is all the land west of the Misty Mountains and North of the river Isen. This is by far the most peaceful of the major regions of middle earth, and is populated by many different races, but primarily hobbits and elves. This land was nearly empty by the end of the Third Age. The main elements of this region are:
The Shire:
The shire is the main dwelling of hobbits. In size it is about 18,000 sqaure miles. It was originally a fertile part of Arnor, and it was kept mainly by gardeners. In 1601 of the Third Age it was given to the hobbits by King Argeleb II. By 1630 of the Third Age most of the hobbits in the world lived peacefully together in the Shire. Only a few hurts have ever befallen the Shire, the two prodominent ones being the Great Plague of 1636 and the Long Winters and the Days of Dearth, between 2758 and 2760 of the Third Age.Its chief cities are Hobbiton and Buckland. Its only distinct physical features are the Brandywine River and the Old Forest. Just beyond Buckland lie the Barrow Downs, which is a land of many hills where mysterious and evil creatures, such as Barrow Wights, dwell. Frodo and his companions almost lost their lives in the Downs, for they were captured by a Wight on the quest of the Ring. They were, fortunately, saved by Tom Bombadil, a mysterious man of the Old Forest.
The Lost Realms of Arnor:
Little is known of this land, other than that it is deserted. It may have served as a hideout for fugitives after Frodo and his companion's "scouring of the shire." It was originally a Dúnadan kingdom, ruled by King Elendil. The Realm of Arnor, unlike the realm of Gondor, also ruled by men, did not flourish or prosper, but was rather forgotten, so that now little is known. Isildur's line always ruled this land. Arnor was also called the North Kingdom.
Harlindon and Forlindon:
Harlindon is a bare coastal land west of Ered Luin. In the beginning of the Second Age, Galadriel and the Celeborn lived in Harlindon. In this land is only the small natural bay of Harlond. The Gulf of Lune separates northern Forlindon, the land east of the northern stretch of Ered Luin, from Harlindon. There is only the river Lhûn in this land, and its mouth, where it empties into the Gulf of Lune and the Great Sea. Gil-Galad, an elven king, lived in Forlindon early in the Second Age.
The Grey Havens:
This city is known as Mithlond in the Elvish tongue, which translates to "Grey Havens." It was founded in the first year of the Second Age. In this city dwell all the remaining Eldar, save those who live in Rivendell. Mithlond is ruled by Círdan the Shipwright, an expert boat craftsman of the First Age. Frodo, Bilbo, Gandalf and Elrond journey here at the end of the Third Age as a way to escape the hassles of a world that has made them heroes.
Rivendell:
Rivendell is the dwelling of Elrond, established in 1697 of the Second Age. Many of the remaining Eldar dwell here, under the rule of Elrond. It is protected on the west by the Bruinen River, which must be forded to reach Riverndell. It is bounded on the east by the Misty Mountains, which protect it from any eastern based attacks. The Bruinen River saved Rivendell from an attack by Ringwraiths, for during the Journey of the Ring, Elrond summoned up the waters after Frodo had forded the river upon his horse, and sent the Ringwraiths downstream in a flood, killing their steeds.Trollshaws:
The Trollshaws is a very small forest where, of old, many trolls dwelt. Origianlly sons of the Kings of Arnor built great cities and castles here, but then the trolls arrived and the people were forced to leave. The surviving three of this area were killed during the Quest of Erebor (Bilbo's Quest) when Gandalf outsmarted them and they were turned to stone by the sun's rays. Many years later, the four hobbits and Aragorn were scared by the stone trolls, not realizing that they were no longer alive.The Mines of Moria:
These once grand halls of the dwarves fell to the hands of orcs long ago. During the Quest of the Ring, the Fellowship was assailed by a Balrog, where Gandalf fell. The entrance lies near a large pond with a strange being living in it. The creature is believed to have been a large squid. The entrance the Fellowship used lies on the western side of the Misty Mountains, where as their exit was upon the eastern. The Bridge of Khazad-Dûm lies in this place. The bridge was destroyed during the Fellowship's visit to the mines.