We stayed for 2 nights at The Manor at Courtland Farm (which is in Aldie, approx 15 minutes from Leesburg).
The house is beautiful. One half is renovated from the original home, and the other half was added to create this hotel (also calls itself a B&B; more on that later). I believe it's been operating since late 2018.
The place is beautifully furnished and immaculate. The manager met us at the door the night we arrived (more on arriving after dark below) and was friendly and gracious. Comfy beds, bare hardwoods, great water pressure in the room. The grounds are beautiful; we didn't have time to explore. There's also a pool, but we didn't check that out.
I would very much recommend this place.
Two areas for improvement, in my opinion:
1. They do call the place a B&B. To me, the second "B" means a real breakfast is made for the guests, not a Continental breakfast. There was make-your-own toast with jellies and butter, donuts, coffee, juice, etc.
2. If arriving after dark, be aware that GPS will get you to the correct road, but it stops at the first bldg (barn) instead of indicating you need to go up a long road--one lane, twisty at times, and unlit. I hope they add more signs to indicate which way to go, as you go a ways before you even see the lights of the place. (Once you do this one time, or in daylight, you're fine.)
The 2 things above are minor, and should not prevent you from going to this lovely place in the middle of the rolling hills and horse farms.