Many of our Presidents were Freemasons, but certainly not all.
There have been 14 in total;
Rumors of presidenal freemasonry ....
Abraham Lincoln was not a Freemason.
Lyndon Johnson received his first degree on October 30, 1937, after receiving the degree he found that his congressional duties (elected in 1937) and dropped out.
President Reagan was not a Freemason although he is an honorary member of the Imperial Council of the Shrine.
George Bush Snr was not a Freemason.
For some excellent references of the History of Freemasonry;