Who is this person?

[Eva Elisabeth]

James Speed.

[RJNorton]

Splendid, Eva! You are correct. Good job!!! Also, congratulations to Roger M. for being so close.

[Eva Elisabeth]

Who is this gentleman?
   

[Gene C]

To me he bears a resemblance to William Crook, well advanced in years.

[RJNorton]

Side view of Horace Greeley?

[Eva Elisabeth]

Brilliant guesses, but, sorry, neither of them.

Hint #1: Gene is right, this photo depicts the gentleman in older age. At the time of Lincoln's death he was in his fourties.

Hint #2: Roger, you are very close in guessing Horace Greeley. He was a journalist, too.

[RJNorton]

OK, Eva, I will stick with the "newspaperman theme."

Noah Brooks in old age?

[Eva Elisabeth]

Good guess, Roger, but this gentleman was much closer to Greeley.

[RJNorton]

Next guess: Charles Dana?

[Eva Elisabeth]

Fantastic, Roger! Well done! It is indeed Charles Dana.

[Eva Elisabeth]

Who is this gentleman?
   

[RJNorton]

Doesn't really look too much like John Nicolay, but it's all that immediately comes to mind. John Nicolay?

[Eva Elisabeth]

Good guess, Roger, but it's not John Nicolay.

Hint #1: In the 1840ies, he moved to Illinois.

[Gene C]

To me, he resembles Joshua Speed (the way his hair sticks out on the side, his eyes, and eyebrows)

http://www.mrlincolnandfriends.org/uploa..._large.jpg
http://www.mrlincolnandfriends.org/photo...hotoID=235

But then again it could be Allan Pinkerton
http://www.americancivilwarstory.com/ima...kerton.jpg

[Eva Elisabeth]

Kudos, Gene, it is Allan Pinkerton. On this photo IMO he resembles Ulysses S. Grant: