Which state is home to 7 of the 10 largest national parks?

Alaska

Explanation:

Alaska is home to 7 of the 10 largest national parks.

These include:

Bering Land Bridge National Preserve

Denali National Park & Preserve

Gates of the Arctic National Park and Preserve

Katmai National Park & Preserve

Kenai Fjords National Park

Kobuk Valley National Park

Sitka National Historical Park

Wrangell-St. Elias National Park and Preserve

Alaska is your answer.