Some links from searching for a rodent rescue in Maryland:
This place in Fredrick seems the most serious about fostering and finding new homes for hamsters etc: http://www.smallangelsrescue.org/
Here's a list of rescues, most of which are in a wide enough radius from Maryland to be in other states. It does mention The Travelling Rat so I guess these are legit:http://rodent.rescueshelter.com/Maryland
The Travelling Rat won't help us with hamsters, but they seem serious enough to have a well-organized website: http://www.thetravelinrat.org/rescue-list--rat-resources.html
This "Rescue Me" site apparently aggregates listings for specific animals and you can see the listings. At the time of writing, there was only one listing for MD and it was for a guinea pig but it was in Howard County: http://rodent.rescueme.org/Maryland
Here is the antique website that has mostly rabbit rescues: http://www.marylandpet.com/rabbit_guinea_pig_ferret_rescue_maryland.htm
