I had always thought that it was. Georgetown (a pre-existing town and now part of the city), I thought, occupied the more attractive non-swampy land.
It turns out that I was wrong. CityHub offers a concise history that refutes the claim. Indeed, if there was any swamp, it was caused in the mid 19th century by massive run off from farming upstream along the Potomac.
One thing all would agree on, however, is that the summer climate sure feels swampy! The heat and humidity get your attention.
My favorite refuge was the underground cafeteria at the National Gallery. It is cool AND it has a waterfall that makes it feel even cooler.
But no, I do not recall the food there.