Actually there was at the very least on Christian Aid Society in the mid century, my suspicion is that there were more. The one I know of was in the NYC area and seems to have had multiple neighborhood based chapters. So instead of assuming that we know what Lauren is looking for why don't we clarify the question.
Lauren - the SA covers several decades and an a remarkably broad spectrum of places and populations. It's often helpful to tip us off as to your place and time frame - even once you have been around for a while since some of us tend to forget
. There was a multitude of religious and semi-religious based aid organizations in the 19th century. If you are indeed looking for something during the Civil War and are looking for a large organization from the Union you likely want one of the two Noah mentioned. If you're looking for something else give us a few more details and someone will likely pop out of the woodwork with some information.
There is a pretty long history of conversations stored here so you might want to acquaint yourself with the search function to see where we might have already gone. The search button is up on the top just below the pictures.