In the nineteenth century, the Finn Valley developed trade in accordance with a farming community. Communications were difficult, and roads bad, so each community had to be self-sufficient, providing their own food, clothing and farming equipment.

There were carpenters, wheelwrights, blacksmiths, weavers and smelters of ore. There was an iron-works at Mullinboy, where farm implements were made of native timber and bog ore. There was a Tannery, at Leatherbrook and a Brickworks at Hallow Road, Castlefin.

Flax was grown and scutched in local mills. Castlefin was a linen-weaving centre. The tall houses in Cross Row on the Diamond, had long, weaving spindles, in their top storeys. There was a spinning-mill on the site of the present day Portico Shirt factory (now Nena Models)

The nineteenth century landlord, Dr. Francis Rogan, built a store on the bridge for storing grain, with a kiln attached for drying it. The dried grain was taken by boat to Strabane and Derry. Dr. Rogan also built a Market-yard, which had a stone tablet over the gate, bearing his name. This was on the site of Patton's house and Castlefin Post Office.

Dr. Rogan was a surgeon in Derry. He visited Castlefin by boat every week. He was a good landlord, who did his best for the well-being of his tenants.

The coming of the Railway in 1863 was a mixed blessing. It opened up the country, and did away with the isolation of the people. But it also did away with the self-sufficiency of the villages. Imported goods were brought in, cheaper to buy than the local craftsmen could make them. Eventually, trade drained away to the bigger towns, like Strabane and Derry, but the good land of the Finn Valley saved the area from extinction.

Things were not always peaceful in those days. From 1799 - 1846 Orange demonstrations were illegal, but in 1846, seventeen lodges marched in Castlefin on 12th July, to the great exasperation of the natives. Both sides were spoiling for a fight, and often had it at local gatherings.