"Knowing all your neighbors and an obsession with high school football define life in an American small town."
But first,
Culture. syn. way of life
2 The ideas, customs, and social behaviour of a particular people or society.
Formally, it is Cultural Geography, "a subfield of Human Geography which focuses “upon the patterns and interactions of human culture, both material and non-material, in relation to the natural environment and the human organization of space” (Cosgrove 1994)"
All that's needed in the sentence is the word way and no more!
"Knowing all your neighbors and an obsession with high school football define the way of life in an American small town."
It works even without that:
"Knowing all your neighbors and an obsession with high school football define life (and culture) in an American small town."
And that's what I'd personally go for.