Is this the one:
1940 United States Federal Census Census & Voter Lists Name James B Mc Keown. Mother Julia Mc Keown Father A Boyd Mc Keown. Birth 1918 - South Carolina. Residence Republic Cotton Mills, Chester, South Carolina. Source Ancestry.com
"United States Census, 1940," database with images, FamilySearch(https://familysearch.org/ark:/61903/1:1:K485-91F : accessed 13 October 2016), James B Mckeown in household of A Boyd Mckeown, Rossville Township, Chester, South Carolina, United States; citing enumeration district (ED) 12-23B, sheet 22A, family 353, Sixteenth Census of the United States, 1940, NARA digital publication T627. Records of the Bureau of the Census, 1790 - 2007, RG 29. Washington, D.C.: National Archives and Records Administration, 2012, roll 3798.