Hmmm, I'm not sure if there's anything that specifically meets that category - but the journal The American Historical Review is the official publication of the AHA, and is largely an extensive amount of reviews of recent works and essays. It's definitely a journal I regularly read to see what new publications and monographs on American history have come out. More than once I've only first heard about, and then read, a work because of the commentary on it that I've seen in this and similar publications.

My specialisation isn't American history, although it is a big area of interest and influence for my own field. I'm sure more specialised American historians can direct you to more specific journals and bibliographic essays on American revolutionary and colonial history.