Ferguson has been variously described as "outside of St. Louis", or as "small town America", and often as a "suburb of St Louis."
These are all misleading.
St. Louis City is an Independent City, like Baltimore and a few others. It is not part of St Louis County. St Louis County surrounds the City of St Louis. The County and the City make up one continuous urban, metropolitan area of close to 2 million people (throw in St. Clair and Madison in Metro East, and St. Charles and Johnson Counties in Missouri, and the St Louis SMSA is about 2.9 mil).
Ferguson is one of maybe 100 municipalities in St. Louis County. I grew up in a neighboring municipality, Florissant, which was then the fourth largest city in Missouri. Our school district was the Ferguson-Florissant School District, and I had a lot of friends, and spent a lot of time in Ferguson. I can remember a girlfriend from rural Illinois asking me, "How do you know what city you're in?" The answer: "By which cops you need to avoid."
The urban area stretches from Florissant/Hazelwood/Spanish Lake in the north down through Jennings, Baden, North St. Louis City, South St. Louis (where my mom's family lived), all the way down through Fenton, Arnold and out towards Eureka and Six Flags and Charleyville in West County. This is a continuous urban area. Had this been Chicago, or New York, or LA, the City would have grown, expanded, and subsumed all the little municipalities in the county, and taken in their populations, their tax bases, and their bureaucracies.
But it didn't. So there are all these little police forces, few of whom have any connection to the population, overlain by the St. Louis County police, who have no connection at all. That lack of connection worked both ways: On the one hand, County might pull you over and hassle you, but the different city cops would bust you and take you in (unless they were your cops and knew you). On the other, the local city cops knew more about you and your places, while County left most places alone.
Main take away: Ferguson is well within the main St Louis metropolitan area, albeit a bureaucratically fragmented area, and is not some outlier community.