Again I am reaching out to the Lutheran list of saints, not that there are not many worthies among the Catholics and Orthodox, but I just think it's good to branch out.
I suspect this saint's name was really Heinrich, since he was born in Einbeck, Hanover (which became Germany about a century after his death). He didn't move to English North America until he was thirty-one years old, and even then he mostly hung out with Germans. I imagine he was only Henry when dealing with colonial governments or preaching to the British.
Although he had a base of three congregations, he preached from New York to Georgia. He addressed German, Dutch, and British audiences, each in their own language. In his forty-five year career, he might rightly be said to have organized the Lutheran Church in the USA.
In 1867, the Allentown (Pennsylvania) Seminary, which evolved into a military institute and then a general college, was renamed in honor of Henry M. Muhlenberg. The College is still affiliated with the Evangelical Lutheran Church in America today. Go Mules!