After consulting the books, you have both species of grays running around all over up there! (both H. versicolor and H. chrysoscelis.)
Maryland looks like it is mostly H. versicolor. Warm rainy nights are best to find them, though it is getting later in the season. A bit of research will lead you to places to look for them on such nights. While I have no experience with H. versicolor, H. chrysoscelis seems to gravitate to outdoor lighting to get an easy meal. Another trick I have not tried personally, is to try playing recorded calls. This can attract both females and satellite males if conditions are right.
I caught another juvenile at work last night! That means both my daughter and I are now at our legal limit for them. However, a local pet shop currently has 5 month old H. versicolor, CB, for 4 dollars each! (Although this particular shop is less than trustworthy....they are more likely captive hatched chrysoscelis which makes them illegal to sell in Nebraska unless documentation proving the source is from another state...)