Ar's Station location an outpost of Great Ar  and trading station on the south bank of the Vosk River , founded four years after Pa-Kur's hordes gathered there, prior to their war against Ar. Ar's station was Ar's stronghold on the Vosk. When Cos  landed at Brundisium , and moved its forces toward Ar's Station, Ar failed to act because of political treachery. Ar's Station eventually fell to Cos. It stands at the northern terminus of the Viktel Aria  which leads to Ar, also known as the Vosk Road.

I had gone from Lara to White Water using the barge canal, to circumvent the rapids, and thence to Tancred's Landing. I had later voyaged down river to Iskander, Forestport, and Ar's StationAr's Station incidentally is near the site where there was a gathering, several years ago, of the horde of Pa-Kur, of the Caste of Assassians, who was leading an alliance of twelve cities, augmented by mercenaries and assassins, against the city of Ar. This war is celebrated, incidentally, in the Gorean fashion, in several songs. Perhaps most famous among them are the songs of Tarl of Bristol.

The action is reputed to have taken place in 10,110 C.A., Contasta Ar, from the Founding of Ar. It was now, in that chronology, the year 10,127. Ar's Station, incidentally, did not exist at the time of the massing of the horde of Pa-Kur. It was established four years afterward, as an outpost and trading station on the south bank of the Vosk. It also commands, in effect, the northern terminus of one of the great roads, the Viktel Aria, or Ar's Triumph, leading toward Ar. This is also the road popularly known as the Vosk Road, particularly by those viewing it from a riverward direction. 
Book 15, Rogue: pp 61-62
"Toward Ar's Station?" I speculated. This was Ar's stronghold on the Vosk. It was situated on the southern bank, east of Jort's Ferry and west of Forest Port, both on the northern bank. 
Book 21, Mercenaries: pg 164
My companion was Marcus Marcellus, of the Marcelliani, formerly of Ar's Station, on the Vosk. 
Book 25, Magicians: pg 16