NTRIP Maryland

Hi James, I use the HxGN SmartNet - Satellite Positioning Service here in Texas and have good results with the service. Or course you have to have cell/internet service in order to use it.
I plugged in some info pertaining to your location into the website subscription calculator and it would run you about $208.33/mo ($2,496.99 + tax for 1yr sub., paid at start of service) for the SmartNet Mid-Atlantic South (5303422) Sub-Regional Coverage—Includes coverage in MD, VA & WV, so not exactly cheap. I pay a little more than 1/2 that amount for state wide service in Texas. Not cheap either, but I wouldn’t be without the service. I envy the states that have free or low cost connections!

Here are a couple of links to the service:
HxGN SmartNet - Satellite Positioning Service
https://www.smartnetna.com/hiw01_intro.cfm
Subscribe
https://www.smartnetna.com/store_product_selector.cfm

And here is a link to their write up on the following question:
Network RTK — Is it worth it?
https://www.smartnetna.com/hiw04_worthit.cfm

Partial Network Coverage Map for your area

And here is another discussion that you might be interested in viewing:

Good Luck, Mark