The new minimum won’t apply to businesses that gross under $500,000 per year or employ fewer than 15 workers. It doesn't apply to employees who work less than 20 hours per calendar year.

The change will put St. Louis’ minimum wage well above that of not just Missouri and Illinois, but of most states, and on par with many larger cities that have set their own rates. Chicago’s current rate, for example, is $10.50 an hour and is set to rise to $11 on July 1.

Supporters of St. Louis’ increase say it will alleviate suffering in a city with a poverty rate approaching 30 percent, almost twice the national average.

The increase in St. Louis will give an immediate raise to an estimated 35,000 workers who will make, on average, $2,400 more each year, said Paul Sonn, general counsel for the National Employment Law Project, a nonprofit that advocates for a higher minimum wage. “That is enough to make a real difference for a waitress or a nursing home worker who is trying to get by on less than $18,000 a year.”