I heard this tidbit of history about 10 years ago, but haven't heard much since. I haven't bothered researching to verify this story. You might know where to look.
D.C. used to be a large tract of land held by a wealthy American who supported the British crown in the War of Independence. This plantation owner was driven off his holdings and went to Upper Canada. The land was hotly contested by several wealthy American families, each using their political influence to acquire it.
This land tract was chosen as the US capital to end a divisive political battle between elites.