Sue Abraham had this newspaper clipping detailing the first Grosvenor Reunion (which we assume was in 1948).
"The first Grosvenor family reunion was held Sunday, Sept. 7, at Fort Kaskaskia near Chester, with a fine dinner at noon and fun afternon of visiting.
Those present were: Mr. and Mrs. Ed Kessel, Mr. and Mrs. Harold Dixon, daughter Roberta and son Merle, Mr. and Mrs. Chester Kessel and family, Mrs. Anna Lee Grosvenor, Mr. and Mrs. Clifford Ray Grosvenor. Mr. and Mrs. Al Strobl, Carl Ray Grosvenor and Paul Claybough, all of Murphysboro. Mr. Fred Grosvenor, Mr. and Mrs. French Grosvenor, Mr. Fred Saul, Mrs. Thelma Ingram and son, Mr. and Mrs. Mack Jarrett and childen, Molly Ann, Kay, Danny and Kenny; Mr. and Mrs. Ernest Pyron, and Mr. and Mrs. Charles Grosvenor, all of Jacob, Mr. and Mrs. Lester Grosvenor, daughter Geraldine and son Leslie Allen, Mr. Park Kessel and Mr. and Mrs. .Kenneth Saul, all of Ava, Mrs. Connie Nelson and son Charles, Vernon, Billy and Harold Welch of Rockwood, Mr. and Mrs. Robert Grosvenor and daughter. Betty, Mr. and .Mrs. Harry Postman and family, all of Chester; Mr. and Mrs. Walter Emert and granddaughter Sue Ellen Mueller of Cora; Mr. and Mrs. Ernest Claussen and daughter Patsy of Trenton, Mr. and Mrs. George Decker and sons of Jackson, Mo., Mr. and Mrs. Charles Saul and Mr. and Mrs. Clyde Saul of Belleville, 111.; Mr. and Mrs. Elmer Grosvenor and son, Mr. and Mrs. John Grosvenor and sons, Mr. and Mrs.; Hugh Harness and daughter, Mr.and Mrs. Henry Thomas and son and Mr. Vernon Welch, all of East St. Louis."