To answer this question, we have to understand that there were two primary reasons that caused the record breaking loss of population you see for the city of St. Louis. For what might be the biggest reason, we need to go back before the turn of the century... not the most recent one either.

In 1870, St. Louis was firing on all cylinders with a gigantic tax base and plenty of new businesses starting. The distant county neighbors of the city were considered a drag on the great city economy. The low population of farmers and tiny cities far away in the county were not trusted to be honest with taxation and the courts were considered corrupt. The general feeling was that the City of St. Louis was giving their county cousins a free ride. It had to stop.

In 1875, legislation was drafted to separate the City of St. Louis from the county and was voted on and (disputably) passed in 1876. Whether or not this vote was failed or crooked is a matter still up for debate, but for some brevity in the answer to your question, let's just say it was approved.

The City of St. Louis was now an Independent City, a county to itself and the borders of the city were permanently set to a city to a 61 square mile limit that ended just outside of Forest Park. To my knowledge, only Washington D.C. and Baltimore are the only other cities to have permanent boundaries. More on this in a moment....but for now, let's move to the 1950's

St. Louis was still doing quite well as a city in the 1950's and 1960's. Because it was considered a prime area to live in, housing was expensive and getting more so. The average St. Louis working family had a choice of either a very convenient St. Louis apartment or, for about the same amount of money, a house with a yard in the county. Due to the new highway system, the affordability of cars, a very robust bus and trolly system, lower taxes and availability of home loans for Korean War veterans, the county started looking very enticing.

As more homes and apartments became available due to people moving to the county, the Black (and displaced) population found that they were now able to move to nicer areas of the city. By roughly the 1970's, "White-Flight" was seriously reducing the population of the city and continued to do so far a few decades on. During this migration, most people simply moved just a few miles outside the city limits.

By the 1980's, the city tax base was eroding and that was reflected in the general upkeep of the city, the schools, and infrastructure. The housing stock of the city was, although charming... old and quite dated. This caused a new peak in migration to the county known as "Black-Flight" to newer houses and neighborhoods, again close to the city, but not inside the limits of the city proper.

Okay.. let's put all of this together now.

If St. Louis was like most other cities in the nation - able to grow and expand without the limitation of permanent borders, you would see that it would be one of the ten largest cities in the U.S. with a population of roughly 3 million in the metro area. However, it's not measured that way.

St. Louis is measured for population, crime, all things good and bad within a 61 square mile area only since it is an Independent City. The metro population, which would have been part of the city had they not set the borders, is never reflected in the totals you see for St. Louis .

There have been several attempts for the city to rejoin with at least St. Louis County, but each time it has failed due to the county residents not wanting to take on the same problems of the city that caused them or their parents to leave in the first place. The good news is that there has been a slight upwards trend of people moving back to the city and rehabbing or developing older neighborhoods. Let's hope it continues as it is a beautiful city with a rich history.