That's an amazing razor. Bigger may not always be better, but it's usually at least cooler.
There was a similiar E. L. & Co Manufactured for the United States on ebay (this one evidently was exposed to less radiation) that ended recently. I mention this because it included what appeared to be the original box which read:
"Edward Leon & Co"
Given that the razor is an 8/8 and the initials match, I feel safe in the assumption that the box is original.
Anyway, the earliest mention of them as a company that I could find is from an 1836 New York directory which places them at 7 Platt.
From 1840:
http://imageshack.us/a/img202/6812/1840.png
Also, they were involved in a court case around 1839, it seems the gov thought they were lying about the purchase price of their imports:
http://imageshack.us/a/img607/3525/federalcases.png
Anyway, by 1859 Edward had brought on several relatives: Abram, Heyman, and Theodore, and were operating out of 28 Dey h 51 London ter. At this time they were operating under the name Leon E. & H. & co. Though they may have continued to use their prior company name. However, if that was not the case, then that suggests that the "Manufactured for the United States" mark does not mean it was produced for use by Union troops.
See here for the 1859 Directory:
Imageshack - 1859.png
Abram is not listed at that residence in 1860.
It may also be worth pointing out this thread, especially posts 4 & 8:
http://straightrazorpalace.com/razor...sheffield.html
This is pure conjecture, but this Edward may be the same as person as the Edward of E. L. & Co. I haven't found any solid evidence to prove that the Edward Leon who lived at 28 Dey was the same person who later lived with at No. 17 Endcliffe Vale. But I did find passport applications from 1859 belonging to an Edward Leon, who was born in Mecklenburg in 1816, who was married to an Emma Leon who was born in Hanover. As well as the passport app (1853) of a Heyman Leon who was born in Mecklenburg in 1820.
Unfortunately it's all circumstantial. Suffice to say that in the 1850's in New York there was a group of Leons importing english cutlery, as well as a group of Leons whose birth places and dates and names match that of an English cutlerer and some of his kin. I didn't go digging through English documents, only American ones. So perhaps someone may shed further light on this issue.