| Name | Deductibility Code |
| Adult Day Care Corporation of Calvert County | -- |
| Affordable Development for All Calvert Inc. | -- |
| American Chestnut Land Trust Inc. | -- |
| Arc of Southern Maryland | -- |
| Autism-Asperger Association of Calvert County Incorporated | -- |
| Barstow Acres Childrens Center Inc. | -- |
| Birthright of Prince Frederick | -- |
| Brem Foundation to Defeat Breast Cancer Inc. | -- |
| Budokan Judo Club of Calvert County Incorporated | -- |
| Calvert Advanced Life Support Unit Inc. | -- |
| Calvert Affordable Housing Alliance Inc. | -- |
| Calvert Alliance Against Substance Abuse Inc. | -- |
| Calvert Animal Welfare League Inc. | -- |
| Calvert County Extension Advisory Council Inc. | -- |
| Calvert County Historical Society Inc. | -- |
| Calvert County Lions Club Inc. | -- |
| Calvert County Literacy Council Inc. | -- |
| Calvert County Public Library Foundation Inc. | -- |
| Calvert County Public Schools Educational Foundation Inc. | -- |
| Calvert County Quilt Guild | -- |
| Calvert Environmental Trust for Youth Inc. | -- |
| Calvert Farmland Trust Inc. | -- |
| Calvert Health System Inc. | -- |
| Calvert Healthcare Solutions Inc. | -- |
| Calvert Hospice | -- |
| Calvert Meals on Wheels Inc. | -- |
| Calvert Memorial Hospital Auxiliary | -- |
| Calvert Memorial Hospital Foundation | -- |
| Calvert Memorial Hospital of Calvert County | -- |
| Calvert Optimist Community Parks Foundation Inc. | -- |
| Calvert Soccer Association Inc. | -- |
| Christmas-In- April-Calvert County Inc. | -- |
| Friends of Calvert County Seniors Inc. | -- |
| Friends of the Calvert County Library Inc. | -- |
| Greater Mount Zion Inc. | -- |
| Greyt Expectations Greyhound Rescue | -- |
| Harms Foundation Inc. | 4 |
| Humane Society of Calvert County | -- |
| John E Harms Jr Foundation Inc. | 4 |
| Kingfish Foundation Inc. | -- |
| Launching Educational Assistance Programs Forward Leap Forward Inc. | -- |
| Learning Disabilities Association of Calvert County Inc. | -- |
| Maryland Association of Area Agencies on Aging Inc. | -- |
| Michael Redmon | 4 |
| New Life Baptists Church | -- |
| On Our Own of Calvert Inc. | -- |
| Pets With Disabilities | -- |
| Philippine Medical Foundation Inc. | -- |
| Prince Frededick Volunteer Fire Department Inc. | 6 |
| Prince Frederick Rotary Club Foundation Inc. | -- |
| Prince Frederick United Methodist Cemetery Corporation | 6 |
| Project Echo | -- |
| Safe Harbor Incorporated | -- |
| Salvation House | -- |
| Southern Maryland Community Development Corporation | -- |
| Southern Maryland Community Network Inc. | -- |
| Southern Maryland Invitational Livestock Expo | -- |
| The Calvert Chamber Foundation Inc. | -- |
| The Celtic Society of Southern Maryland Inc. | -- |
| The United Way of Calvert Inc. | -- |
| Whole Heart Deliverance Temple Ministries Inc. of Prince Frederick | -- |
| Widowed Persons Service of Calvert County Inc. | -- |