The American Revolution in 1776 ended the "Old Colonial System" under which colonial exports were restricted to British territory. Glasgow's status as the tobacco entrepôt ceased with trade with America outlawed, though experienced Glasgow merchants were well placed to continue the trade direct to Europe until the French Revolution (1789) and subsequent war intervened. After 1815 the tobacco entrepôt faded, though processing for the British market continued. Even before 1776 West Indian trade had overtaken North American, and sugar became the great re-export, processed in Clydeside's many "Sugar Houses". The islands of the West Indies also consumed many Glasgow exports with shipping in 1790 exceeding that to both the USA and Europe.
This expansion was partly because new plantations supplied Glasgow's increasing cotton mills. But West Indian dominance died with slavery in 1833, while connections with North America were growing fast after 1815. Southern States Cotton was imported and settler and slave goods exported as relations with ex-colonies were rebuilt. Trade with Latin America began as independence swept through the Spanish Empire. More important, however, was the flood of emigrants from Scotland to Canada which took off in the 1780s with recurrent crop failures in Argyll and war-induced distress around Glasgow. Settlers needed the usual things: household goods, linens and cottons, books, second-hand clothes, and in one shipment a pre-fabricated school and all its contents.
Timber production and shipbuilding organised by Glasgow firms were of great importance for future developments. Transatlantic liners were the forerunners of the Clyde-built steamers; the British & North American Royal Mail Steam Packet Company's Britannia (1839) put Glasgow in the grand shipping league even before the company’s clumsy name was changed to Cunard.