I wanted to find a good account of the original event, when General Gordon Granger read the proclamation on the balcony of Ashton Villa in Galveston on June 19, 1865. I was hoping for a contemporaneous account in a Galveston newspaper, but I couldn't find one. The best I could do was this entry in Wikipedia.
Although it probably didn't happen on the exact date (although it may have), here's a brief account of emancipation in Sugar Land back in June 1865. It comes from A. J. Sowell's History of Fort Bend County, which the Fort Bend County Historical Commission is reprinting. It will be available later this summer.
The author visited Cunningham's plantation in the late 1890s and talked with Aunt Sarah Chase, a former slave on the Terry Plantation. Here's a little background on how she got to Sugar Land and her brief recollection of her first day of freedom.
I've tried to determine who Judge Buckner was, but I haven't had any success. I'm fairly certain he was not a Fort Bend County judge.