$15 million to spend on a home. where do you buy?

Hill Country

I would leave the country with 15 million. Our southern border is going to be the end of the county. No reason to stay here with that kind of wealth.

Key West

Lake house on Lake LBJ around Horseshoe Bay.

Sullivan's Island South Carolina

Texas first. However, I'd research the previous 30 years of tax assessors in the country and how they act. In my county, they're total f@*$ retards about raising property values (and hence taxes), even when there are massive local layoffs.

But in a county 15 miles away they didn't. Pick the county carefully.

Based on the subject but ruined by at least one of your criteria my answer coming in was Incline Village aka Billionaires Row on Lake Tahoe. Arguably the most beautiful lake in the US you can boat on, surrounded by gorgeous land, and has great skiing all around you in the winter. Summer outdoor activities are great too.

Somewhere with elk, grizzly bear, good streams, mule deer, and a buncha cattle.

Ten years ago I would've probably said a Hill Country ranch but not anymore. I really fell in love with the area east of Canyon, TX. I'd buy several thousand acres of canyonland and build a nice home on the rim. Canyon is a nice, clean, and safe town just south of Amarillo. While the panhandle is ugly as shite, the areas near Caprock and Palo Duro are gorgeous.

Something like this

I'd go with more land and less house, just giving an example.

This house is ugly as hell but this is where I would build.

Outer Banks. Hatteras Island to be specific. Probably moving there after complete retirement without the full 15 mil anyways.