Distance new york city to washington dc

The Smithsonian museums on the Mall are a true highlight, but given they can take about an hour to get into at peak times and you can easily spend a half day / day in each one (think there is 11 of them) then you will miss this. I'd really suggest you reconsider this as you really won't get to see anything in a day. If you do decide to go then outside the station there will be bus tours, but you just will not see half of DC and from a bus seat it's not much fun.

Bit like trying to see all of London in 4 hours. A day is just not enough to see anything in DC.