On November 14, 1937, one-hundred and three new, current, and re-instated members of the Knights of Columbus from Harlingen, Rio Hondo, San Benito, La Feria, Mercedes, Raymondville, and Santa Rosa joined together in the institution of Fr. Peter Keralum Council No. 2785.

Fr. Peter Keralum Council No. 2785 was named after Fr. Pierre Yves Kéralum OMI (1817-1872) he was a French-born Catholic missionary and member of the Missionary Oblates of Mary Immaculate. He served in South Texas from 1853 to 1872, traveling long distances on horseback to minister to Catholics living on isolated ranches along the Rio Grande. He was also an architect who designed many buildings in the area, including the Immaculate Conception Cathedral in Brownsville, Texas. His remains were originally interred in Mercedes, Texas before being transferred to San Antonio, Texas.