Up to the 19th century the urban settlement area was enclosed by a city wall, with the outer ring wall being created following the great earthquake of 1356. While this was built significantly larger than the first one, the city grew only moderately over the course of the next 500 years. The population fluctuated between 6,000 and 12,000 inhabitants, with epidemics regularly causing a decline in population.

In the second half of the 19th century Basel evolved from a fortified small town to a medium-sized industrial city with the population growing from 20,000 to 110,000 inhabitants within 70 years. The city fortifications were demolished after 1860 and new districts were built. The affluent bourgeoisie moved away from the crowded inner city out to the new districts. At the same time, the first quarters for the working class were erected. In the early decades of the 20th century the built-up areas reached the canton and national borders, with the city and suburbs merging into a trans-boundary agglomeration.