… just not necessarily mine.
The core came from Christian western Europe with the settlers. It was refined and influenced by the unique circumstances, environment, etc., they encountered here. It was greatly influenced by the aforementioned pioneer spirit. Also, by other groups of people, the Indians who were already here, the slaves brought from Africa, etc.
It was molded by the challenges of “taming a continent,” as I once read — masterfully illustrated, to me, by George Caleb Bingham’s painting of Daniel Boone leading settlers through the Cumberland Gap — the different terrains, range of climate and temperature, etc. (I was pretty young when I read this, so don’t remember the source, but it said houses up north were given steep roofs to shed snow while houses in the South were given lower/flatter roofs with wide overhangs and/or deep porches for shade, and often with an open dogtrot to catch breezes).
These challenges enhanced the division of labor between men and women, although other cultures also had a similar divisions. Men explored, hunted, cleared land and built, women birthed children and cared for them, grew and prepared food, spun and weaved and sewed. Tradesmen, merchants, shippers, etc., followed the pioneer explorer and settlers into newly opened areas and created first trading posts, then small settlments, which grew into small towns, and some into cities.
Navigable rivers influenced settlement areas (and served as communication arteries), as did terrain and fertility of the soil; for example, there weren’t wide-ranging, midwestern-style farms or huge plantations in Appalachia. The plains of the west where buffalo herds once lived were adaptable o raising domestic herds (sheep, cattle).
It is my belief that the influence of Christianity enhances man’s God-given ability to explore and invent, and the population of that area of North America that would become the USA proved creatively inventive in meeting the challenges of making the land habitable and starting trade. Although it is taboo to say so, Christian Europe also influenced the notions of government in the New World, and this is one reason it is difficult to transplant western style democracy onto cultures such as Iraq, so that our “nation building” in such places is pretty much doomed to failure. (Due to character limits on comments, I will have to continue this thought in another comment.)
My answers to you are of necessity very rudimentary and piecemeal. My notions about such things were developed over my lifetime, from many different sources. I could not name them all for you. Some of the information was likely mistaken, some of it filtered through my own perceptions. But believe the information my concept of American culture is, on the whole, valid — regardless of the hideous cackles of ridicule it might provoke in my critics.