In the case of this bucolic hideaway in Marin, 48 acres isn't the size of the hamlet you're living in, it's the size of your private property.

Imagine breathing in the woodsy air from the poolside garden. Or by a trickling koi pond. Or curled up in the mahogany-clad library. To complete this peaceful picture? Your kids (or in-laws) trotting about with the horses.

For true serenity, this private enclave encompasses an entire valley reminiscent of a healing retreat: birds chirping, deer in the distance, and greenery as far as the eye can see—you'll find hiking trails, a meditation cave, a treehouse with, and even an exotic bird aviary. The house itself is strikingly modern—three buildings are connected villa-style by a long, glass-enclosed hallway. The concrete fireplace in the living room features an intricate foliage motif to rival any hearth in a grand Scottish castle. Even the guest house is has its own luxe master bath with a custom European tub and floor-to-ceiling windows.