I would modify this and say that about $100,000 is the very lowest at which a family anywhere can be considered upper middle class. That would depend on family size, state of residence and the CoL of the area.
According to the Census Bureau, the median income for a family of four is $68,000. However, in Mississippi the median income for a family of four is $51,800, while in Maryland, the median is $92,500. So the definitions of upper middle class would be different in each of those states.
I would consider 150% or so of the median and higher to be upper middle class, while upper class is the top 5% or so to be wealthy. Of course, other things to be taken into consideration, like accumulated wealth. So a family of four which owns a $1,000,000 house, fully paid for, has $5,000,000 in savings, and has an income of $200,000 is wealthy, while a family of four with $30,000 equity in their house and $50,000 in saving, and has an income of $200,000 is still upper middle class. Of course if a family has two kids in college versus two kids in elementary school, the income which puts them in upper middle class.
It also depends whether the lower cutoff for wealthy is the top 20%, the top 10%, the top 5%, or the top 1%.