George Rogers Clark was the Revolutionary War General who captured the Northwest Territories. He never married but had 9 siblings. William Clark, the youngest brother, was of Lewis and Clark fame. He had 7 children. I've not been able to find much on the Web about these folks.
Family tradition says they are related.
Here is some of what I've been able to uncover from traditional sources. Niemantsverdriet - Three brothers left Holland separately to seek their fortunes in the new world. Every Niemantsverdriet we've ever found is a relative of these three. Stein - Jacob Stein left Hamburg for NY at age 17 or 19. Married and prospered in Petersburg, IL, where he knew A. Lincoln.