One and a half centuries ago, St. Louis had the highest percentage of immigrants of any U.S. city. Fully half the 160,000 residents in 1860 were foreign-born.

Most numerous were Germans (54 percent) and Irish (32 percent) with a sprinkling of English, French, Swiss and Bohemians, according to the Missouri Historical Society.

Chicago and the Northeast's growing industrial sector beckoned, however, and by 1920, St. Louis occupied the other extreme, possessing the nation's lowest foreign-born percentage.

The dearth of immigrants to St. Louis for most of the rest of the 20th century was the very factor that eventually led to a sharp upsurge the past two decades.

When the refugee stream to the U.S. rose in the 1980s, resettlement officials looked for places to send the people fleeing war, persecution or oppression. St. Louis was attractive because immigration was not an issue that aroused passions, acrimony or even much discussion.

Rather, it was viewed as a safe and hospitable place for refugees, with a diverse job market, affordable housing and three refugee resettlement agencies - including the nationally renowned International Institute of St. Louis.

Similarly, as economic immigrants from Mexico, Central America and elsewhere began to flee crackdowns in California and other traditional destinations in the 1990s, St. Louis loomed as a quiet and tolerant place, away from the resentment found in states grappling with overrun schools or hospitals and with questions of legal status.

By the mid-1990s, the St. Louis region was reaching a critical mass of foreign-born residents, and the flow took on a self-reinforcing nature. Refugees who had been resettled in other cities picked up and moved here, drawn by a growing kinship network. And while immigrants previously had often arrived in St. Louis as a secondary destination after leaving states like California or Texas, as word spread more made St. Louis their initial choice.

For the past two decades, U.S. Census figures show the region's flow of immigrants and refugees far outpacing the national average, jumping by 32,000 in each decade - to 82,000 from 50,000 over the 1990s, and to 114,000 by 2008 and about 120,000 now.

Over the past 20 years, St. Louis has averaged more than 3,200 immigrants a year (nine arriving every day) in a region with an otherwise stagnant population.

Since 2000, St. Louis has seen a 40 percent rise in immigrants, and the local percentage growth was even steeper in the 1990s, at more than 60 percent.

And yet St. Louis continues to be seen nationally and by its residents as a city that is framed in white and black, and is rarely mentioned in the immigration discussion.

There are two principal reasons.

First, the foreign-born stream to the region is highly diverse. A multitude of small- or mid-sized groups arrived gradually and are threaded throughout the city, surrounding counties and the Metro East area.

Second, St. Louis has a disproportionate share of refugees, who tend to arouse sympathy rather than hostility, given the often-tragic factors that led them to flee their homeland. Often educated, they are not seen as an economic drain in the way that impoverished immigrants frequently are. And questions about their legal status are rare, given the highly regulated manner in which they are resettled.