Wow! This one was tough. Here's my thought process: I found a format in the Chicago style guide for citing a letter to the editor, so I used that rather than treating it as a web site or a manuscript collection. It's logical that the history citation format would want to know the original, rather than the current format. Then I added on the information for articles retrieved online. The authors names were cited according to Chicago conventions. The location of the original publication was added as per Chicago requirements for unknown publications. If you need to break the URL, break it after one of the slashes. You will want to correct the access date. Don't forget to indent the first line of the footnote.
Money Hunter, et al., letter to the editor, Cherokee Phoenix and Indians' Advocate (New Echota, Cherokee Nation, GA), March 4, 1829. http://www.cherokee.org/AboutTheNation/History/TrailofTears/ObjectiontoRemoval-1829.aspx (accessed November XX, 2014).
Good luck with you paper!
