Before I begin, anything that's blue is a link...while the PRO-94 will pick up some things, most all of Washington County's law and other stuff has moved to a digital platform that the 94 won't handle. See our listing in the database
Washington County, Maryland (MD) Scanner Frequencies and Radio Frequency Reference
Take note of the 'Tag' column - if it says 'Deprecated', the frequency has been abandoned by the user.
Now go down to the very bottom, where the various trunked systems in Washington county are listed. There's a listing for FiRST there - this is a statewide system that already has an operational site in the County. This uses a modulation type that can only be copied by a handful of scanners, listed here...
APCO Project 25 - The RadioReference Wiki
These scanners will also handle the analog stuff that's still active, as well as other trunked types.
FiRST will only continue to grow - I would suspect that there will be more than one site in Washington County in the future. You should consider buying for that future growth
We have a LOT of scanner information in our wiki. Notice that the models listed there are in blue - click on them to read up on them. Also keep in mind that given the County's very hilly terrain, an external antenna is practically a must if you want to hear anything from any distance away. This should also be a part of your decision.
Mike