| Oakwood Lake Dam Forrest County | 15 | — | Low | Not Rated |
| Oakview Drive Dam Panola County | 34 | 2004 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-40 Dam Benton County | 28 | 1975 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-35 Dam Benton County | 30 | 1974 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-21 Dam Benton County | 26 | 1963 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-17 Dam Benton County | 28 | 1963 | Low | Poor |
| Oaklimeter Creek Watershed Structure Lt-8-16 Dam Benton County | 26 | 1963 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-14 Dam Benton County | 26 | 1963 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-12 Dam Benton County | 26 | 1963 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-11 Dam Benton County | 27 | 1963 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-09 Dam Benton County | 26 | 1969 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-06 Dam Benton County | 22 | 1959 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-05 Dam Benton County | 26 | 1959 | Low | Not Rated |
| Oaklimeter Creek Watershed Structure Lt-8-04 Dam Benton County | 25 | 1959 | Low | Not Rated |
| Oakley Lake Dam Oktibbeha County | 10 | — | Low | Not Rated |
| Oak Hills Lake Dam Lincoln County | 17 | — | Low | Not Rated |
| Oakes Lake Dam Attala County | 12 | — | Low | Not Rated |
| Nutt Lake Dam Madison County | 28 | 2008 | Low | Not Rated |
| Nunnery Lake Dam Pike County | 14 | — | Low | Not Rated |
| Noxubee Game Farm Lake Dam Noxubee County | 12 | — | Low | Not Rated |
| Nortrust Farm Management Lake Number 2 Dam Hinds County | 17 | — | Low | Not Rated |
| Nortrust Farm Management Lake Dam Hinds County | 18 | — | Low | Not Rated |
| North Tippah Watershed Structure Lt-6a-14 Dam Tippah County | 26 | 1967 | Low | Not Rated |
| North Tippah Watershed Structure Lt-6a-02 Dam Tippah County | 28 | 1962 | Low | Not Rated |
| North Tippah Watershed Structure Lt-6a-01 Dam Tippah County | 24 | 1962 | Low | Not Rated |