| Circle Health ServicesEIN 23-7078501 | Health | OH | $5,547,953Mid-sized | 88.77 |
| Citizens Against Government WasteEIN 52-1363952 | Human and Civil Rights | DC | $3,768,713Mid-sized | 83.69 |
| Citizens Commission on Human RightsEIN 68-0005541 | Human and Civil Rights | CA | $3,592,409Mid-sized | 80.30 |
| Citizens United for Research in EpilepsyEIN 36-4253176 | Health | IL | $6,070,422Mid-sized | 96.46 |
| Citizens United FoundationEIN 54-1626748 | Human and Civil Rights | DC | $3,554,360Mid-sized | 56.74 |
| City AcademyEIN 31-1619379 | Education | MO | $3,936,148Mid-sized | 86.36 |
| City MissionEIN 25-1051749 | Human Services | PA | $6,720,515Mid-sized | 82.31 |
| City Mission of SchenectadyEIN 14-1403652 | Human Services | NY | $5,157,949Mid-sized | 99.34 |
| City of RefugeEIN 58-2194642 | Human Services | GA | $8,064,665Mid-sized | 86.10 |
| City Rescue MissionEIN 59-1009115 | Human Services | FL | $5,461,593Mid-sized | 79.84 |
| City Rescue Mission of SaginawEIN 38-1368362 | Human Services | MI | $5,610,309Mid-sized | 94.69 |
| City Rescue Mission, Oklahoma CityEIN 73-0713883 | Human Services | OK | $6,209,143Mid-sized | 89.00 |
| Clark County Food BankEIN 91-1307564 | Human Services | WA | $11,160,692Mid-sized | 99.08 |
| Clarke Schools for Hearing and SpeechEIN 04-2104008 | Education | MA | $11,678,628Mid-sized | 82.72 |
| CLASPEIN 23-7000150 | Research and Public Policy | DC | $6,942,104Mid-sized | 95.42 |
| Classroom CentralEIN 03-0455618 | Education | NC | $5,729,370Mid-sized | 94.74 |
| Classroom, Inc.EIN 13-3666846 | Education | NY | $4,643,853Mid-sized | 87.65 |
| Clean Air Task ForceEIN 04-3512550 | Research and Public Policy | MA | $5,368,687Mid-sized | 93.52 |
| Clean Water FundEIN 52-1043444 | Environment | DC | $5,390,587Mid-sized | 90.03 |
| Cleveland Animal Protective LeagueEIN 34-0714644 | Animals | OH | $5,028,954Mid-sized | 90.02 |
| Cleveland Botanical GardenEIN 34-0239538 | Environment | OH | $7,054,254Mid-sized | 72.19 |
| Cleveland Sight CenterEIN 34-0714652 | Human Services | OH | $10,147,874Mid-sized | 94.07 |
| Climate CentralEIN 26-1797336 | Environment | NJ | $9,872,125Mid-sized | 84.53 |
| COA Youth & Family CentersEIN 39-0806339 | Human Services | WI | $7,224,306Mid-sized | 98.69 |
| Coachella Valley Rescue MissionEIN 95-2684844 | Human Services | CA | $7,269,992Mid-sized | 96.83 |
| Coaching CorpsEIN 94-3310845 | Human Services | CA | $4,311,471Mid-sized | 90.46 |
| Coalition for Christian OutreachEIN 25-1216330 | Religion | PA | $12,058,281Mid-sized | 95.67 |
| Coalition for the HomelessEIN 13-3072967 | Human Services | NY | $11,680,807Mid-sized | 89.70 |
| Coalition for the Homeless of Central FloridaEIN 59-2814255 | Human Services | FL | $5,987,495Mid-sized | 91.40 |
| Coalition on Temporary ShelterEIN 38-2420565 | Human Services | MI | $8,585,803Mid-sized | 89.88 |
| Coalition to Abolish Slavery & Trafficking (CAST)EIN 10-0008533 | Human Services | CA | $3,782,163Mid-sized | 90.07 |
| Coalition to Salute America's HeroesEIN 52-1351773 | Human Services | VA | $12,071,141Mid-sized | 70.20 |
| Coast Guard FoundationEIN 04-2899862 | Human Services | CT | $6,525,302Mid-sized | 83.53 |
| Coast Guard Mutual AssistanceEIN 31-1801931 | Human Services | VA | $3,792,602Mid-sized | 93.15 |
| Coastal Conservation LeagueEIN 57-0887278 | Environment | SC | $3,691,863Mid-sized | 91.84 |
| Coastal Maine Botanical GardensEIN 01-0476545 | Environment | ME | $4,847,073Mid-sized | 85.71 |
| COCAEIN 43-1395056 | Education | MO | $5,999,290Mid-sized | 83.54 |
| Cocoon HouseEIN 91-1497667 | Human Services | WA | $4,854,869Mid-sized | 87.51 |
| Collaborative for Academic, Social, and Emotional LearningEIN 20-5884201 | Education | IL | $6,773,512Mid-sized | 88.56 |
| College Now Greater ClevelandEIN 34-6580096 | Education | OH | $12,466,427Mid-sized | 95.47 |
| Collision Repair Education FoundationEIN 36-3768028 | Education | IL | $11,564,561Mid-sized | 92.54 |
| Colorado Education InitiativeEIN 26-1597530 | Education | CO | $7,489,959Mid-sized | 85.38 |
| Colorado Springs Fine Arts CenterEIN 84-0406947 | Arts, Culture, Humanities | CO | $6,797,225Mid-sized | 90.71 |
| Colorado Springs Philharmonic OrchestraEIN 74-3091110 | Arts, Culture, Humanities | CO | $3,917,452Mid-sized | 85.50 |
| Colorado SymphonyEIN 84-0511458 | Arts, Culture, Humanities | CO | $13,000,490Mid-sized | 82.60 |
| Colorado UpLiftEIN 84-0889330 | Education | CO | $5,716,706Mid-sized | 87.29 |
| Colorectal Cancer AllianceEIN 86-0947831 | Health | DC | $6,452,188Mid-sized | 90.18 |
| Columbia Lighthouse for the BlindEIN 53-0196609 | Human Services | DC | $6,245,235Mid-sized | 76.66 |
| Columbia Museum of ArtEIN 57-6007869 | Arts, Culture, Humanities | SC | $4,269,010Mid-sized | 78.98 |
| Columbus Citizens FoundationEIN 13-6118967 | Education | NY | $4,362,512Mid-sized | 85.20 |
| Columbus Symphony OrchestraEIN 31-6402408 | Arts, Culture, Humanities | OH | $8,505,883Mid-sized | 86.14 |
| Committee for Accuracy in Middle East Reporting in AmericaEIN 52-1332702 | International | MA | $4,796,135Mid-sized | 93.69 |
| Committee on Temporary ShelterEIN 03-0285606 | Human Services | VT | $3,566,411Mid-sized | 88.33 |
| Committee to Protect JournalistsEIN 13-3081500 | Human and Civil Rights | NY | $7,345,573Mid-sized | 92.83 |
| Common Cause Education FundEIN 31-1705370 | Human and Civil Rights | DC | $7,223,861Mid-sized | 93.96 |
| Common Counsel FoundationEIN 94-3214166 | Community Development | CA | $3,914,023Mid-sized | 85.93 |
| Common HopeEIN 41-1560297 | International | MN | $4,867,551Mid-sized | 94.76 |
| Common ThreadsEIN 20-0106847 | Human Services | TX | $3,810,395Mid-sized | 91.24 |
| CommonwealEIN 94-2366094 | Health | CA | $4,034,106Mid-sized | 93.02 |
| Communities in Schools of Charlotte Mecklenburg, Inc.EIN 58-1661795 | Education | NC | $6,728,143Mid-sized | 92.07 |