Permanent American presence next to this geographic feature is currently maintained by ► McMurdo Station.
It's not in the continental United States, but this geographic feature completely surrounds a Roosevelt Island. Vance Woodall was accidentally crushed to death on this geographic feature while participating in Operation Highjump. Several expeditionary bases named "Little America" were established by Richard (*) Byrd on top of this geographic feature. If you traveled directly south from the non-Canadian Scott Island, your boat would crash when it collided with this geographic feature. Permanent American presence next to this geographic feature is currently maintained by ► McMurdo Station. The Bay of Whales, which no longer exists, formed a harbor on this geographic feature where Roald Amundsen established the Framheim base. For 10 points, name this largest ice shelf in Antarctica, located within New Zealand's claimed dependency.
It's not in the continental United States, but this geographic feature completely surrounds a Roosevelt Island.
Ross Ice Shelf [or McMurdo Ice Shelf until "McMurdo" is read; accept answers like "Ross Sea" because that's what it floats on]