Maryland. In the past year I’ve had to board twice thanks to a surprise pregant mare:
I paid $840/month for full pregnant mare care (with an extra foaling fee). It was 100% all inclusive and included monitoring, grooming, anything needed to keep a pregnant mare comfortable. She also offers regular boarding which I think is a bit cheaper, but I didn’t ask the current rate. She has basic riding facilities and everything you need.
Then I paid $350/month for basic care at my friend’s boarding and lesson farm at weaning time. It included 24/7 turnout in a field with shelter, feeding 2x a day, plus fly spray/blanketing. I had to provide my own feed, hay, and all other necessary care items. But it was full care in the sense she kept them fed, watered, and safe. Her place has a nice barn with climate controlled tack room, an outdoor arena, and round pen. I would have been happy to be there full time back in my boarding days.
Neither place is “high end” but both provide top notch care and have everything you need to keep a horse in work most of the year.