| O'Donnell | Jas. sen. | Annie Brook, Quindalup | OD1 | 1924 |
| O'Donnell | John | Sandstone | 1DO | 1912 |
| O'Donnell | John Patrick | Bangemal, Carnarvon | J2D | 1912 |
| O'Donnell | John Patrick | Bangemal, Carnarvon | J2d | 1924 |
| O'Donnell | M. | Merrebin, Katanning | 1OD | 1912 |
| O'Donnell | M. | Rose, Narra Tarra | 2ED | 1912 |
| O'Donnell | M. | Rose Valley, Narra Tarra | MD5 | 1912 |
| O'Donnell | M. | Merrebin, Katanning | 1OD | 1924 |
| O'Donnell | M. | Rose, Narra Tarra | 2ED | 1924 |
| O'Donnell | M. | Rose Valley, Narra Tarra | MD5 | 1924 |
| O'Donnell | M. | Martindale, Katanning | 0DE and 42C, 5A | 1962 |
| O'Donnell | M. | Merridin, Katanning | 1OD and 6C, 14E | 1962 |
| O'Donnell | P. E. & V. D. | Morrell Hills, Katanning | 1PD and 14B, 39E | 1962 |
| O'Donnell | Patrick John | Binnu | P0D | 1928 |
| O'Donnell & Co. | C. S. | Windbridge, North Burracoppin | U6F and 23B, 49E | 1962 |
| O'Donnell & Sons | S. J. | Faraway, Binnu | S4J and 13D, 114E | 1962 |
| O'Donohoe | B. | Wiluna | E0D | 1912 |
| O'Donohue | B. | Wiluna | E0D | 1924 |
| O'Donohue | John | Bamboo Springs, Nullagine | C6V | 1924 |
| O'Donovan | Clair | Blocks 129 & 130, Kwollyin A. A. | C8D | 1912 |
| O'Donovan | Claire | Blocks 129 and 230, Kwolyn A. A. | C8D | 1924 |
| O'Donovan | W. de B. | Kokebin, Kellerberrin | OD6 | 1912 |
| O'Donovan | W. de B. | Kokebin, Kellerberrin | OD6 | 1924 |
| O'Dorisio | C. & P. | Brookside, Waroona | C6O and 115A, 44C | 1962 |
| O'Driscoll | A. T. | Olive Grove, Harvey | D6U | 1924 |
| O'Driscoll | Humphrey | Commonage, Nullagine | O9D | 1924 |
| O'Driscoll | J. | Seatle Ross, Boyup Brook | GE5 and 45C, 12E | 1962 |
| O'Driscoll & Haly | - | Blocks 11469 & 11520, Yorkrakine | 3DH | 1912 |
| O'Driscoll & Haly | - | Blocks 11469 and 11520, Yorkrakine | 3DH | 1924 |
| O'Driscoll & Son | P. | Baltimore, Grass Valley | P0D and 35D, 3E | 1962 |
| O'Driscoll Bros | - | Horse Hill Shamrock Ville and Chilamoning, Grass Valley | K0D and 9B, 23E | 1962 |
| O'Dwyer | Kate | State Forrest, Mullewa | 0DK | 1924 |
| O'Dwyer | Sister M. C. | Presentation Covent Grounds, Geraldton | 5PC | 1912 |
| O'Dwyer | T. K. | Tara, Yorkrakine | 0TK | 1912 |
| O'Dwyer | T. K. | "Tara," Yorkrakine | 0TK | 1924 |
| O'Dwyer | W. | Avon 12914, 11459, Yorkakrine | 7WO and 45B, 71E | 1962 |
| O'Farrell | J. F. | Pioneer Dairy, Beecboro | JO9 and 108B, 30A | 1962 |
| O'Farrell | Patrick | Commonage, Mount Morgans | P0F | 1912 |
| O'Farrell | Patrick | Commonage, Mount Morgans | P0f | 1924 |
| O'Gorman & Bernhard | - | Lewis Island, Roebourne | 07B | 1912 |
| O'Gorman & Bernhard | - | Lewis Island, Roebourne | O7B | 1924 |
| O'Grady | F. B. | Kent Loc. 1393, Jerramungup | F6G and 38B, 10A | 1962 |
| O'Grady | Henry Jas. | Modana Station, Derby | O1G | 1924 |
| O'Grady | James | Collie-Burn, via Collie | OG9 | 1924 |
| O'Grady | L. | Avon Loc. 14397, Mt. Marshall | NG4 | 1924 |
| O'Grady | L. | Pantapin | L0G | 1928 |
| O'Grady | L. & J. | Kalindiri, Pantapin | JO1 and 39A, 47E | 1962 |
| O'Grady | M. W. | Nullagine | W2C | 1912 |
| O'Grady | M. W. | Nullagine | W2C | 1924 |
| O'Grady | Michael | Mt. Marshall, Kellerberrin | MG4 | 1924 |
