The 1820s and 1830s saw the fastest rate of growth of Glasgow's population as people were pulled by the new economic opportunities in the city. Although growth slowed over the succeeding decades, the city continued to attract young migrants until after the First World War. In 1851 only 44 per cent of citizens had actually been born in the city; 35 per cent came from other parts of Scotland. Most came from within a thirty-mile radius, but a few travelled greater distances.
There was a well-established tradition of seasonal migration from the West Highlands, but, as the process of Highland clearances spread, more made the city their permanent home. A steady flow of immigrants from Ireland became a flood in the late 1840s when the potato crops failed in successive years. In the early months of 1848 some 1,000 per week were arriving in Glasgow. Altogether nearly 43,000 arrived in the first four months. In the 1851 census, 18.2 per cent of Glasgow's population were Irish-born, predominantly from towns in the northern counties. As the century progressed the numbers coming from Ireland shrank so that by the time of the 1911 census only 6.7 per cent were Irish-born.
It was after 1860 that small numbers of Italians began to appear in Glasgow. Many of them initially were pedlars and carvers of plaster religious figurines. From the 1880s increased numbers, mainly from two areas, Barga in Lucca-Tuscany and Picinisco in Lazio, began to settle in the West of Scotland. A number of those from Barga found a niche as proprietors of fish and chip shops, while those from Picinisco seem to have turned to the ice-cream trade.
The great growth in Jewish immigration came after 1890 as many fled pogroms in Russia, Poland and Lithuania, although there had been a synagogue in the city from 1823. The more established Jewish community had settled in the north of the city, with a new synagogue being established in Garnethill in 1879, but the bulk of the new migrants settled in the Gorbals. By 1901 the Jewish population was more than 6,000. Many were small businessmen, especially in tailoring, while others found work in Mitchell's cigarette factory.
In 1911 56 per cent of the population had been born outside of the city and 1.7 per cent had been born outside the British Isles.