No Separation

Riddle me this: If there is "Separation of Church and State" in the United States then why are people forced to vote in Churches, Synagogues and other places of worship?

 When I lived in Virginia the "Good Ole Boys" down there tried to make me vote in one and I refused - not because I'm not religious (although my Polling Station wasn't the same denomination as I am) but because I believe in the true principal of "Separation of Church and State." I was able to vote at the County Offices.