The sunflower family is large, and many species fall under the category of "sunflower" as a common name. It is also not uncommon for them to grow to this height or even taller. This could be a species of Helianthus, the most commonly-encountered of the sunflowers, but we cannot be more certain until it flowers. (Even then, they can be challenging to tell apart because they are so similar.) Jerusalem Artichoke (Helianthus tuberosus) is one possibility as it is known to be a bit weedy in MD. While native to much of the U.S., it is unclear whether or not it is considered truly native to MD as various sources seem to disagree on its original native range.

Most perennial sunflowers bloom late in the year; Jerusalem Artichoke, for instance, doesn't bloom until mid-September or so into October. If this plant is old enough to flower, you may see buds developing in the next few weeks. When it blooms, you're welcome to send an updated photo for another attempt at ID, which you can attach to a reply here.

Miri

Thank you for your interesting, helpful and hopeful information. I look forward to sending an update. 

Thank you for your interesting, helpful and hopeful information. I look forward to sending an update. 

You are welcome.