I wrote this article for Lubavitch.com
I like it so much, though, that I'm putting here as well:
Mikvah Excavation Confirms Observance of Ritual Among Early Jews in America
According to Dr. Jonathan Sarna, Joseph H. & Belle R. Braun Professor of American Jewish History at Brandeis University, “the more we know, the clearer it becomes that the mikvah was important to early Jews [in America].” Though in the United States, mikvahs older than the Baltimore mikvah built in the 1840s have yet to be discovered, “there is not a scintilla of a doubt” that older mikvahs did exist. Sarna notes synagogue minutes in the communities of Philadelphia and New York that record the upkeep of local mikvahs, as part of a “astonishing reminder that religion [along with mikvah observance] was central [to Jewish life].”The paucity of information until now led many to assume that early Jewish settlers in the New World, largely composed of Iberian Jewish refugees, were not careful in mikvah observance. Max I. Dimont, a historian and author of several popular works on Jewish History, was of the opinion that the early settlers “had simply rejected the entire institution [of mikvah].” Recent discoveries of mikvahs in the early Jewish communities of Recife, Brazil and on the islands of St. Eustatius and Barbados in the Caribbean, have refuted this notion.