2: This Van Halen song is named for a car and not the Central American country of the same name.
clam (background music: don't know much about geography; don't know much about popular music; woe is me)
4: Toto sang, "I know that I must do what's right / As sure as" this mountain "rises like Olympus above the Serengeti."
6: This band was no longer a "transit authority" when it released "25 or 6 to 4" in 1970.
Manhattan Transit Authority
8: In 2010, Brian Kelley and Tyler Hubbard founded this country music group in Nashville, Tennessee that is named for a more southerly feature.
10: Taken literally, this two-word nonexistent place where a "city boy" was "born and raised" in a Journey song may be Windsor, Ontario.
3: According to the census results, New York was the most populous state; this neighboring state was 2nd.
6: First used in the 1890 census, Herman Hollerith's tabulator was fed data recorded on this specific medium.
I'm almost prepared to guess "ticker tape," but I think I need to clam on this one.
9: The 1890 Census found that this part of the American landscape no longer existed; Frederick Jackson Turner wrote about its significance in American history.
12: Most of the data from the 1890 census was destroyed in a 1921 fire in a building housing this cabinet department that now administers the census.
15: The least populous state, with 47,355 residents, was this state that lost nearly 15,000 in the previous decade after a mining bonanza subsided.