Organizations
Largest first
By revenue on the last return. Organizations that file Form 990-N report no figures and come last.
| Organization | Return | Revenue |
|---|---|---|
| National Aquarium IncBaltimore | Form 990 | $54,351,794FY2025 |
| The Maryland Zoological Society IncBaltimore | Form 990 | $24,960,748FY2025 |
| Alley Cat Allies IncorporatedBethesda | Form 990 | $22,273,205FY2025 |
| The Humane LeagueRockville | Form 990 | $22,145,897FY2025 |
| American Association of Zoological Parks and Aquariums IncSilver Spring | Form 990 | $20,870,405FY2024 |
| Gentle Giants Draft Horse Rescue Society LtdMount Airy | Form 990 | $11,704,633FY2025 |
| Aaalac International IncFrederick | Form 990 | $9,709,785FY2025 |
| Born Free USA United with Animal Protection InstituteSilver Spring | Form 990 | $8,346,516FY2025 |
| Maryland SPCA IncBaltimore | Form 990 | $8,194,527FY2025 |
| Baltimore Animal Rescue and Care Shelter IncBrooklyn | Form 990 | $7,977,497FY2025 |
| Last Chance Animal Rescue IncWhite Plains | Form 990 | $6,745,834FY2025 |
| American Fisheries Society IncBethesda | Form 990 | $6,147,310FY2024 |
| Humane Society of Washington County IncorporatedHagerstown | Form 990 | $3,683,461FY2025 |
| Montgomery County Humane Society IncRockville | Form 990 | $3,614,368FY2025 |
| Days End Farm Horse Rescue IncWoodbine | Form 990 | $3,540,102FY2025 |
| Wildlife Habitat Council IncBethesda | Form 990 | $3,516,103FY2024 |
| Alley Cat Rescue IncMount Rainier | Form 990 | $3,281,075FY2025 |
| The Wildlife SocietyBethesda | Form 990 | $3,234,614FY2025 |
| Humane Society of Baltimore County IncReisterstown | Form 990 | $3,186,895FY2025 |
| Ferry Cove Shellfish IncSherwood | Form 990 | $3,025,657FY2025 |
| Center for a Humane Economy IncBethesda | Form 990 | $2,886,334FY2025 |
| Defenders of Animal Rights IncPhoenix | Form 990 | $2,873,857FY2025 |
| Hart for Animals IncMcHenry | Form 990 | $2,862,357FY2025 |
| Global Wildlife Trust IncThurmont | Form 990 | $2,754,192FY2025 |
| Humane Society of Harford County IncFallston | Form 990 | $2,650,085FY2025 |
| Society for the Prevention of Cruelty to Animals of A A Co MD inAnnapolis | Form 990 | $2,647,387FY2025 |
| Animal Outlook IncTakoma Park | Form 990 | $2,261,995FY2025 |
| Waterfowl Festival IncEaston | Form 990 | $2,162,654FY2025 |
| Humane Society of Carroll Co IncWestminster | Form 990 | $2,000,986FY2025 |
| Plumpton Park Zoological Gardens IncRising Sun | Form 990 | $1,893,584FY2025 |
| Humane Society of Wicomico County IncSalisbury | Form 990 | $1,811,049FY2026 |
| Talbot Humane CoEaston | Form 990 | $1,702,213FY2025 |
| Animals Angels IncorporatedWestminster | Form 990 | $1,580,746FY2025 |
| Rude Ranch Animal Rescue IncMillersville | Form 990 | $1,373,321FY2024 |
| Humane Society of Kent County IncorporatedChestertown | Form 990 | $1,358,670FY2025 |
| Foxie G Foundation IncUnion Bridge | Form 990 | $1,308,065FY2025 |
| Patuxent Animal Welfare SocietyHuntingtown | Form 990 | $1,304,369FY2025 |
| Companions and Animals for Reform and Equity IncBaltimore | Form 990 | $1,145,864FY2024 |
| Second Chance Wildlife Center IncClarksburg | Form 990 | $1,121,021FY2025 |
| Allegany County Animal Shelter Management FoundationCumberland | Form 990 | $1,051,182FY2025 |
| Worcester County Humane Society IncorporatedBerlin | Form 990 | $1,012,840FY2025 |
| Lab Rescue of LRCP IncorporatedLutherville | Form 990 | $988,078FY2024 |
| Wildfowl Trust of North America IncGrasonville | Form 990 | $961,257FY2025 |
| Poplar Spring Animal Sanctuary IncPoolesville | Form 990 | $951,868FY2024 |
| Humane Society of Charles County IncWaldorf | Form 990 | $910,409FY2025 |
| Centre for Wildlife Studies IncBethesda | Form 990 | $837,043FY2024 |
| Small Miracles Cat and Dog Rescue IncEllicott City | Form 990 | $828,252FY2025 |
| Caroline County Humane Society IncRidgely | Form 990 | $809,846FY2025 |
| The Humane Society of Dorchester County IncCambridge | Form 990 | $780,534FY2025 |
| Frederick County Humane Society IncFrederick | Form 990 | $775,265FY2024 |
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