Why would someone try to hack into my Facebook Acct?

I have a FB Acct. that I rarely use this last year. I have used it mostly to post photo albums for long distance friends. I have, just in the last week, visited a few times after a long period of inactivity.Today I received an alert from FB security saying that somebody attempted to access my acct. from a suspicious, unknown source that originated in Kansas. I know nobody in Kansas, not now, not ever. Can anyone explain why this happened? I changed my password, but, not being super high tech I am bewildered.