Flordell Hills has 822 residents living on about a dozen streets in less than a square mile. It is now the 58th police force for the mosaic of 90 municipalities that make up St. Louis County. More than a third of the county’s population is covered directly by the county police, as residents in unincorporated areas or communities that contract with the county.

Fitch and others have suggested the move is driven by a desire to raise more revenue through traffic stops.

Last year, more than 40 percent of the town’s revenue came from its municipal court, according to a study by Better Together, a nonprofit group that is looking at how the region can be more efficiently organized.

A Post-Dispatch study found that Flordell Hills issued the equivalent of about two traffic tickets per resident last year and just a slightly lower number of nontraffic citations.

The city is a sort of island surrounded by Jennings, from which it once contracted for police services. A scandal prompted Jennings to dissolve its force and contract with the county in 2011.