We agree the Robinia species in our region can be difficult to tell apart at this point (being both young and dormant) and we don't have a good resource that points-out the nuanced differences between the two species. Given how abundant Black Locust is in Maryland, it's likely to be that species, since Clammy Locust is quite rare (at least, few observations have been documented so far). We're pretty confident this is not a Honeylocust, though. If you decide to keep the plant for now, it might be easier to concretely identify once in bloom or producing seeds, though even one of our reference books states that Robinia species are sometimes very hard to distinguish from one another.

Miri

Thank you so much for your quick response! I didn’t realize clammy locust was quite so rare. I will keep an eye out on it as it blooms this summer, with great interest.

You're welcome!