St. Louis is a deceptive case. The city and county are split into separate governments-- the city overwhelmingly Dem, the county much stronger Republican. Depending on how they calculate statistics, it can be deceptive of the area as a whole-- it is NOT more liberal than New York.
The County of St. Louis excludes the city of St. Louis. It is very confusing I admit. Typically, a city is within the county of the same name. Another is Baltimore County, which also excludes the city.