[Rumierules]

I wonder how many counties with around 300,000 or more people are red?

Duval County, Florida (Jacksonville) is purple now.

[SSS Two]

I wonder how many counties with around 300,000 or more people are red?

Red Texas counties with population greater than 300,000:

970,000 Collin County (Plano)
836,000 Denton County (Frisco)
537,000 Montgomery County (The Woodlands)*
362,000 Brazoria County (Pearland)
347,000 Bell County (Killeen)
335,000 Galveston County (League City)
305,000 Lubbock County (Lubbock)

* Montgomery County typically provides the most net Republican votes (GOP - Dem) in Texas.