We have found very cheap flights to the US capital, which are starting from 251EUR return with British Airways from both Dublin and Shannon. As you would expect there are tonnes to do around Washington D.C including the White House, Washington Monument, Lincoln Memorial and loads more.
Below are the sample dates for these flights from Dublin are below and you can change the date to check other available dates by clicking the screenshot below.
Dublin flight dates:
The Shannon to Washington flight dates are as follows: