Two governments share one name, and your keyword list has to choose
The City of St. Louis is an independent city, legally separate from St. Louis County, and searchers behave as though they are two markets because they are.
Almost nowhere else in the country is set up this way. National agency templates get it wrong constantly, and a local reader notices inside one sentence. The county line is a real phrase here, used in ordinary conversation about where a business sits.
The practical effect is that your keyword set splits in two. Someone pricing warehouse space inside the city is not satisfied by a page about the county, and the reverse is worse: county inventory sold to a city search wastes both the click and the position.
Build the split into structure, not just wording. Separate pages, separate URLs, separate internal links, and a plain statement on each of which jurisdiction it covers. For anything procedural, point readers at the relevant municipal or county office rather than answering for them.
The vocabulary follows the split. City pages can carry the Central West End, Soulard, The Hill and Dogtown. County pages carry Clayton, Brentwood, Maplewood, Kirkwood and Chesterfield. One page trying to hold all of it ends up ranking for your firm's own name and little else.