Only Springfield is a song that was sung in the episode Walking Big & Tall. It was the Springfield national anthem until Moe found out that every other city had that same anthem and they replaced it with Why Springfield, Why Not.
Hans Moleman: There's a special little place.
A special smile on every face.
A town called Springfield.
Citizens of Springfield: Special buildings, special sky.
A unique place to live and die.
Of all the cities on the mappy,
you're the one that makes me happy.
Joe Quimby: Only Springfield!