All of the Nest and Habitat locations in Maryland are found here: http://pkmngotrading.com/wiki/Maryland Please let us know if there are any inaccuracies with the spawn locations or if you know more Nests and Habitats in Maryland.
Gambrill State Park, MD Charmander Nest survived the change Severn-Danza Park In Severn, MD is a Squirtle Nest that also survived.
The visitors center at Antietam National Battlefield in Sharpsburg, MD is an active Seel nest, was a Doduo nest previously.
Allen pond park switched from sandshrew to female nidoran. Fort armistad changed from charmander to squirtle. Severn danza park is still a squirtle nest.
Bauer Community Center on Bauer Drive & Norbeck Rd in Rockville is a Squirtle Frequent Spawn Point (I live within walking distance, I catch several a day there, already about to evolve my second blastoise) Olney Manor Park in Olney, MD is a nest, just switched over to an Electabuz nest from the recent update, was a Syther nest before that.
There is a Montgomery County Reddit page, and they have put together this map, it may help: https://www.google.com/maps/d/u/1/viewer?usp=sharing&mid=1fcfie3jD407ifR8VZxLVEGO_NkI
Theres a kabuto nest on sligo creek parkway towards downtown s.s. also, used to be a jynx nest but is now an electbuzz nest at MLK swimming pool in Silver spring
Maryland city park is a Charmander nest confirmed. 565 Brock Bridge Rd, Laurel, MD 20724 Also severn danza park is no longer squirtle seems like its nothing now