| Citymeals-on-WheelsEIN 13-3634381 | Human Services | NY | $20,441,242Large | 90.36 |
| CitySquareEIN 75-2332948 | Human Services | TX | $20,653,887Large | 92.74 |
| Clare Boothe Luce Policy InstituteEIN 54-1672138 | Human and Civil Rights | VA | $1,351,379Small | 94.63 |
| Clark County Food BankEIN 91-1307564 | Human Services | WA | $11,160,692Mid-sized | 99.08 |
| 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 |
| Clean Air Task ForceEIN 04-3512550 | Research and Public Policy | MA | $5,368,687Mid-sized | 93.52 |
| Clean Ocean ActionEIN 22-2897204 | Environment | NJ | $581,461Small | 92.82 |
| Clean Water FundEIN 52-1043444 | Environment | DC | $5,390,587Mid-sized | 90.03 |
| Clearwater Free ClinicEIN 59-1852871 | Health | FL | $3,222,946Small | 92.22 |
| Clearwater Marine AquariumEIN 59-2086737 | Animals | FL | $15,652,675Large | 95.87 |
| Cleveland Animal Protective LeagueEIN 34-0714644 | Animals | OH | $5,028,954Mid-sized | 90.02 |
| Cleveland International Film FestivalEIN 34-1262368 | Arts, Culture, Humanities | OH | $3,287,755Small | 93.55 |
| Cleveland Museum of Natural HistoryEIN 34-0714338 | Arts, Culture, Humanities | OH | $18,722,320Large | 90.29 |
| Cleveland Public TheatreEIN 34-1359225 | Arts, Culture, Humanities | OH | $2,140,830Small | 92.22 |
| Cleveland Sight CenterEIN 34-0714652 | Human Services | OH | $10,147,874Mid-sized | 94.07 |
| Clothes To KidsEIN 14-1849798 | Human Services | FL | $1,221,078Small | 91.27 |
| 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 Homeless of Central FloridaEIN 59-2814255 | Human Services | FL | $5,987,495Mid-sized | 91.40 |
| Coalition to Abolish Slavery & Trafficking (CAST)EIN 10-0008533 | Human Services | CA | $3,782,163Mid-sized | 90.07 |
| 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 |
| Cold Spring Harbor LaboratoryEIN 11-2013303 | Research and Public Policy | NY | $147,631,524Large | 92.80 |
| College Bound, MOEIN 20-4768985 | Education | MO | $2,509,817Small | 91.73 |
| College Now Greater ClevelandEIN 34-6580096 | Education | OH | $12,466,427Mid-sized | 95.47 |
| College PossibleEIN 41-1968798 | Education | MN | $16,391,039Large | 91.38 |
| College TrackEIN 94-3279613 | Education | CA | $18,429,592Large | 96.15 |
| Collision Repair Education FoundationEIN 36-3768028 | Education | IL | $11,564,561Mid-sized | 92.54 |
| Colorado Center on Law and PolicyEIN 84-1264154 | Research and Public Policy | CO | $1,154,061Small | 92.33 |
| Colorado Children's CampaignEIN 74-2374672 | Human and Civil Rights | CO | $2,182,396Small | 91.93 |
| Colorado Public RadioEIN 74-2324052 | Arts, Culture, Humanities | CO | $17,648,179Large | 95.44 |
| Colorado Springs Fine Arts CenterEIN 84-0406947 | Arts, Culture, Humanities | CO | $6,797,225Mid-sized | 90.71 |
| Colorectal Cancer AllianceEIN 86-0947831 | Health | DC | $6,452,188Mid-sized | 90.18 |
| Columbus Museum of ArtEIN 31-4379447 | Arts, Culture, Humanities | OH | $13,970,682Large | 91.73 |
| Columbus Zoo and AquariumEIN 31-4390844 | Animals | OH | $71,124,051Large | 92.24 |
| Combined Jewish PhilanthropiesEIN 04-2103559 | Community Development | MA | $166,682,869Large | 94.56 |
| CommentaryEIN 13-3610041 | Arts, Culture, Humanities | NY | $3,059,126Small | 90.59 |
| Commission To Every NationEIN 74-2730294 | Religion | TX | $17,045,573Large | 96.46 |
| Committee for Accuracy in Middle East Reporting in AmericaEIN 52-1332702 | International | MA | $4,796,135Mid-sized | 93.69 |
| 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 HopeEIN 41-1560297 | International | MN | $4,867,551Mid-sized | 94.76 |
| Common Sense MediaEIN 41-2024986 | Arts, Culture, Humanities | CA | $22,906,362Large | 93.91 |
| Common ThreadsEIN 20-0106847 | Human Services | TX | $3,810,395Mid-sized | 91.24 |
| CommonBond CommunitiesEIN 41-1260469 | Community Development | MN | $13,518,416Large | 92.27 |
| CommonwealEIN 94-2366094 | Health | CA | $4,034,106Mid-sized | 93.02 |
| CommonwealthEIN 04-3540147 | Community Development | MA | $1,993,340Small | 91.42 |
| Communities Foundation of TexasEIN 75-0964565 | Community Development | TX | $129,532,950Large | 91.42 |
| Communities In Schools National OfficeEIN 58-1289174 | Education | VA | $20,927,294Large | 90.78 |
| Communities in Schools of Charlotte Mecklenburg, Inc.EIN 58-1661795 | Education | NC | $6,728,143Mid-sized | 92.07 |
| Communities in Schools of ChicagoEIN 36-3591326 | Education | IL | $2,653,240Small | 91.75 |
| Communities In Schools of HoustonEIN 76-0031827 | Education | TX | $12,788,149Mid-sized | 91.61 |
| Communities In Schools of NevadaEIN 88-0292094 | Education | NV | $6,748,695Mid-sized | 91.30 |
| Community Action Stops AbuseEIN 59-2114359 | Human Services | FL | $4,663,766Mid-sized | 92.75 |
| Community Catalyst EIN 04-3355127 | Human and Civil Rights | MA | $12,149,963Mid-sized | 91.21 |
| Community CoalitionEIN 95-4298811 | Community Development | CA | $5,163,415Mid-sized | 91.86 |
| Community CooperativeEIN 59-2602772 | Human Services | FL | $3,203,307Small | 90.68 |