There are currently 19 Westron Baronies in the Valley of the Old Ones. Technically speaking, there are 18 Baronies, and the city of Narn, which is the capitol of the Kingdom of Ymnaris - of which the 18 other Baronies are technically fiefdoms. However, in practice, Ymnaris (currently ruled by Duke Alasdair IV of the Neill family) is little more powerful than some of the other larger baronies. The two points of exception for Narn are its size (it is larger, by thousands of inhabitants, than the next largest Baronial city), and the fact that the Cathedral of St. Narn is there - for which the city is named. The Cathedral of St. Narn is also the seat of the Church (technically, the "High Office at St. Narn of the Westron Church of the Three Goddesses").
The Cities (which are technically named for the barony of which they are the capitol) all have their own "official" nick name. They were all settled between the years 26 and 1186. It is currently the year 1534 of the Western Migration, so the younger cities have only been established as short as 300 years since they were originally settled, compared to the oldest, which has been settled now for over 1500 years.
The population figures given are JUST for the City, and not for the whole Barony. In most cases, assume that the Barony will number this much again in dependent towns, and double this amount in dispersed rural communities.
So other than the city of Narn, the other 18 Baronies are as follows:
Hogle - "The First City" in the Shattered Plains region; pop. 18,000, settled year 26.
Macester - "City of the Sword" in the Gateway region; pop. 21,000, settled year 82.
Ockham - "City of Enchantment" in the Enchanted Forests region; pop. 19,000, settled year 107.
Scallen - "City of Birds" in the Bartaloo region; pop. 19,500, settled year 163.
Kof Karn - "City in the Cradle" in the Rising Land region; pop. 21,000, settled year 219.
Khomaes - "City of Mists"; in the Darkearth Plains region; pop. 22,000, settled year 231.
Henn - "City of the Shadows" in the Rising Land region; pop. 18,000, settled year 285.
Pellorix - "City of the Lake" in the Rising Land region; pop. 19,000, settled year 341.
Werms - "City in the Clouds" in the Darkearth Plains region; pop. 19,000, settled year 352.
Huygen - "City of Light" in the Darkearth Plains region; pop. 18,500, settled year 394.
Gorrem - "City of Ten Gates" in the Wychwood region; pop. 27,000,settled year 462.
Na Kram - "City of Dust", in the Sildur Reaches region; pop. 18,000, settled year 558.
Lynch - "City of Fire" in the Nightside region; pop. 20,000, settled year 642.
Botts - "City of Wind" in the Sildur Reaches region; pop. 17,500, settled year 728.
Ungams - "City of the Harp" in the Nightside region; pop. 16,000, settled year 902.
City of Narn - "City of the Three Goddesses" Capitol of Kingdom of Ymnaris; in the Suuviz region; pop. 38,000, settled year 914.
Devrie - "City of Shale" in the Shale March region; pop. 16,000, settled year 1022.
Futtonol - "The Shield City" in the Suuviz region; pop. 11,000, settled year 1099.
Kennidor - "City on the Frontier" in the Shale March region; pop. 12,500, settled year 1186.
Note that the nicknames of the city are those that the Archivists at Parn Tandalorn have decided to grant the city, in order to differentiate the City itself form the Barony, which often includes lands, villages, castles and other holdings far beyond the borders of the city. The local inhabitants, however, will sometimes choose a different name (either from custom, or predating the naming by the Archivists). For instance, the inhabitants of the First City (capitol of the Barony of Hogle) often refer to it as Granite Hold - which was the name of the Castle first built there by the founding baron, Sir Tuneyer of Ockett, in the year 26. It took him, and his men, a number of years to build Granite Hold, but they adopted for a stone structure from the start, hence the name.