From Stamps of the World
Horsham is a market town on the upper reaches of the River Arun in the centre of the Weald in Sussex, England. The first historical record of Horsham is from AD 947. The name may mean either "horse home" or "Horsa's home" (a Saxon warrior who was granted land in the area). The town has historically been known for horse trading in early medieval times, iron and brick making up until the 20th century, and brewing more recently. Horsham has developed beyond the original boundaries to incorporate some of the smaller hamlets which now form part of the outer districts. Horsham was given the Post Office numeral of 381 in 1844, its sub office at the Railway Station was also given its own duplex 381 in the 1880's to handle its own mail.
Horsham Station Office
The railway station, Horsham, is on the Arun Valley Line from Chichester to Crawley, Gatwick and London Victoria. Trains on this line start from Bognor Regis or Portsmouth and Southampton Central, and are coupled at Horsham. Southbound ("down") trains divide here. Between 1859 and 1867 the station was enlarged on several occasions to coincide with the doubling of the branch line from Three Bridges; the extension of the railway from Horsham along the Arun Valley Line; the opening of new lines from Horsham to Shoreham via Steyning and from Christ's Hospital to Guildford. Finally, in 1867 a new route to Dorking, Leatherhead and thence to London, was opened. The station was again partially rebuilt and resignalled, with three signal boxes, in 1875. It had its own station post office at the station and was given its own duplex cancellation of 381 in the 1880's