Was my home water for almost 20 years. In general it will be high and dirty, but if you go further up or try Cabin Branch, which is a smaller tributary, you may have some luck.
From Rt 97 take 650 going w/nw then make a right on Hipsley Mill. You will come to a bridge - that is the Patuxent you can try up or down stream. If that does not look good you can cross the river and keep going. Hipsley Mill intersects with Annapolis Rock Rd. This is where you can enter Cabin Branch and fish south back towards the Patuxent.
You can also go further up the Patuxent there are several intersections that cross the river.