The 15 largest independent physician groups 

HealthCare Partners IPA is the largest independent physician group in the country, according to a July 26 report from Definitive Healthcare. 

Definitive Healthcare tracks more than 122,000 physician groups in the U.S.  

Here are the 15 largest independent groups along with the number of physicians they employ, according to Definitive Healthcare. 

1. HealthCare Partners IPA (Garden City, N.Y.): 4,891
2. Santa Clara County IPA (San Mateo, Ca.): 857
3. IPA of Nassau & Suffolk Counties (Commack, N.Y.): 799
4. Patient Physician Network IPA (Plano, Texas): 519
5. Mount Auburn Cambridge IPA (Brighton, Mass.): 367
6. Torrance (Calif.) Memorial IPA Medical Group: 352
7. Allcare IPA (Modesto, Calif): 277
8. Valley Care IPA (Camarillo, Calif.): 238
9. St. Vincent IPA Medical Group (Vista, Calif): 183
10. Lakewood IPA (Compton, Calif.): 145
11. Greater Tri Cities IPA Medical Group (Vista, Calif.): 130
12. Independent Emergency Physicians (Farmington Hills, Mich.): 109
13. Independent Hospitalists (Anthem, Ariz.): 96
14. Santa Barbara Select IPA (Oxnard, Calif.): 87
15. Allied Pacific IPA Healthcare City (Alhambra, Calif.): 22