Rick DiMare Dug this up in his studies of Georgism and Henry George's writings. It was called the Georgist Constitution. He writes:
"The following Georgist platform was adopted on September 3, 1890 in Coopers Union, New York, on the final day of a 3-day convention, the first national convention in Georgist history, and only a few months before Henry George had a stroke that would cause him to withdraw from the movement (though he kept writing important works until he died in 1897)."
"The event was remarkable, as hundreds of delegates attended from nearly every state in the union. It was after this convention that Georgism entered a new phase, one that sought federal and international recognition. This month (August 2015) the movement’s 115th annual convention was held in Detroit."