The city of Baltimore’s population has been in decline throughout much of the 20th century. While the suburban county population continues to grow with the development of the Baltimore–Washington, D.C., corridor, the city population in 2001 was 635,210, down 11.5 percent from 1990. Baltimore became an important port of entry for immigrants during the 1820s. As the eastern terminus of the National (Cumberland) Road that ran across the Appalachian Mountains, it was a natural starting point for recently arrived immigrants seeking land in the interior of the country. Like most Atlantic seaboard cities, Baltimore received significant numbers of French exiles during the French Revolution and the early part of the ensuing revolutionary wars (1789–95). By 1860, more than one-third of the population was foreign born, including large German and Irish communities. During the great wave of new immigration between 1880 and 1920, Baltimore, and most eastern seaboard ports, received immigrants from dozens of countries, with Italian and Greek communities becoming especially prominent. Baltimore was not a popular immigrant destination after 1920. See also Maryland colony.